Communication device and method for radio communication

ABSTRACT

A communication device is provided that includes a baseband circuit and a transmitter configured to transmit a first signal and a projected signal. The baseband circuit is configured to determine the projected signal based on an estimated signal state information such that an energy of a shaped projected signal is smaller than an energy of a shaped signal. The estimated signal state information is an estimate of a signal state information based on the first signal and a received signal that is received by a receiver of the second communication device. The shaped projected signal is the projected signal received by the receiver of the second communication device and filtered by a filter of the second communication device. The shaped signal is the received signal filtered by the filter of the second communication device.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.16/490,117 filed with the USPTO on Aug. 30, 2019, which is a nationalstage entry according to 35 U.S.C. § 371 of PCT Application No.PCT/US2018/022295 filed on Mar. 14, 2018, which claims priority toEuropean Patent Application Serial No. 17 164 234.1 filed on Mar. 31,2017, all of which are incorporated herein by reference in theirentirety.

TECHNICAL FIELD

The present disclosure relates to communication devices and methods forradio communication.

BACKGROUND

In a scenario, a base station provides a wireless connection in afrequency range of an incumbent base station to a communication device.The communication device may be connected to another communicationdevice via another wireless connection. It may be desirable to minimizean interference of signals of the base station with received signals ofthe other wireless connection that are received by the communicationdevice.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. The drawings are not necessarilyto scale, emphasis instead generally being placed upon illustrating theprinciples of the disclosure. In the following description, variousaspects of the disclosure are described with reference to the followingdrawings, in which:

FIG. 1 shows a schematic drawing of a mobile radio communication systemthat may be configured to operate as a Licensed Shared Access (LSA)system;

FIG. 2 shows a schematic drawing of a scenario in which a secondcommunication device, the first base station and a sixth communicationdevice may be configured to connect via radio frequency connections;

FIG. 3 shows a schematic diagram of a communication device that mayinclude a transmitter and a circuit;

FIG. 4 shows a schematic diagram of a communication device that mayinclude a transmitter and a circuit;

FIG. 5 shows a schematic diagram of a scenario of a base station and sixcommunication devices;

FIG. 6 shows a schematic diagram of a communication device that mayinclude a transmitter and a circuit;

FIG. 7 shows a schematic diagram of a communication device that mayinclude a transmitter and a circuit;

FIG. 8 shows a schematic diagram of a scenario in which a sixthcommunication device may be configured to transmit signals in a firstcell based on a shared frequency range;

FIG. 9 shows a schematic diagram of a communication device that mayinclude a receiver and a circuit;

FIG. 10 shows a schematic diagram of a scenario in which a use of theshared frequency range is restricted in an Exclusion-, Protection- orRestriction zone;

FIG. 11 shows a schematic diagram of a scenario in which the basestation may be configured to provide a radio frequency connection to thefourth communication device;

FIG. 12 shows a schematic diagram of a scenario in which the fourthcommunication device may be moved to the shared area to the firstsector;

FIG. 13 shows a schematic diagram of a scenario in which the fourthcommunication device may be moved in the shared area to the secondsector;

FIG. 14 shows a schematic diagram of a scenario in which the fourthcommunication device may be moved in the shared area to the thirdsector;

FIG. 15 shows a schematic diagram of a communication device that mayinclude a receiver and a circuit;

FIG. 16 shows a schematic diagram of a scenario in which a first basestation may be configured to provide radio frequency connections basedon a first frequency;

FIG. 17 shows a schematic diagram of a first communication device thatmay include a receiver, a determination circuit and a circuit;

FIG. 18 shows a schematic diagram of the second base station that mayinclude a transmitter, a receiver and a circuit;

FIG. 19 shows a schematic diagram of a fourth communication device thatmay include a receiver and a circuit;

FIG. 20 shows a schematic diagram of a selection scenario which may bebased on the first communication device, the second base station and thefourth communication device;

FIG. 21 shows a schematic diagram of a communication system that mayinclude a first communication device and a base station;

FIG. 22 shows a method for radio communication;

FIG. 23 shows a method for radio communication;

FIG. 24 shows a method for radio communication;

FIG. 25 shows a method for radio communication;

FIG. 26 shows a method for radio communication;

FIG. 27 shows a method for radio communication;

FIG. 28 shows a method of operating a communication device; and

FIG. 29 shows a schematic diagram of a communication device.

DESCRIPTION

The following detailed description refers to the accompanying drawingsthat show, by way of illustration, specific details and aspects in whichthe disclosure may be practiced.

The word “exemplary” is used herein to mean “serving as an example,instance, or illustration”. Any aspect or design described herein as“exemplary” is not necessarily to be construed as preferred oradvantageous over other aspects or designs.

A “circuit” may be understood as any kind of a logic implementingentity, which may be special purpose circuitry or a processor executingsoftware stored in a memory, firmware, or any combination thereof.Further, a “circuit” may be a hard-wired logic circuit or a programmablelogic circuit such as a programmable processor, e.g. a microprocessor. A“circuit” may also be a processor executing software, e.g. any kind ofcomputer program. Any other kind of implementation of the respectivefunctions which will be described in more detail below may also beunderstood as a “circuit”. It is understood that any two (or more) ofthe described circuits may be combined into a single circuit withsubstantially equivalent functionality, and conversely that any singledescribed circuit may be distributed into two (or more) separatecircuits with substantially equivalent functionality. In particular withrespect to the use of “circuitry” in the claims included herein, the useof “circuit” may be understood as collectively referring to two or morecircuits.

A first communication device may be located in a restricted zone inwhich an incumbent base station provides radio frequency connections ina shared frequency range. A second communication device, e.g. a basestation, may receive approval to connect via radio frequency connectionsin the shared frequency range in a transmission area that overlaps withthe transmission area of the incumbent base station. The incumbent basestation receives signals from a third communication device in the sharedfrequency range. The second communication device utilizes the firstcommunication device to reduce the interference energy that theincumbent base station receives from the second communication device.Further, the second communication device utilizes the firstcommunication device to reduce the interference energy that theincumbent base station receives from a fourth communication device.

Various aspects of this disclosure provide a communication device thatmay include a circuit and a transmitter configured to transmit a firstsignal and a projected signal. The circuit may be configured todetermine the projected signal based on an estimated signal stateinformation such that an energy of a shaped projected signal is smallerthan an energy of a shaped signal. The estimated signal stateinformation may be an estimate of a signal state information based onthe first signal and a received signal that is received by a receiver ofa second communication device. The shaped projected signal may be theprojected signal received by the receiver of the second communicationdevice and filtered by a filter of the second communication device. Theshaped signal may be the received signal filtered by the filter of thesecond communication device. Thus, the communication device may beconfigured to effectively reduce the impact of interference signals onthe second communication device. Further, the communication device maybe configured to determine a reduced interference signal independentfrom feedback of the second communication device. Moreover, thecommunication device may be configured to flexibly adapt the reductionof the impact of interference signals to the filter of the secondcommunication device.

The present disclosure provides a communication device may include acircuit and a receiver configured to receive signals from a firstcommunication device. The circuit may be configured to determine aformed signal based on a location information of a second communicationdevice such that a received second energy based on the formed signalthat is received from the second communication device is smaller than areceived first energy based on the formed signal that is received fromthe first communication device. Thus, the communication device isconfigured to reliably and efficiently reduce the received interferenceenergy of a second communication device relative to the firstcommunication device. Further, the communication device may beconfigured to flexibly reduce the received interference energy of abroad range of communication devices.

Various aspects of this disclosure provide a communication device thatmay include a receiver configured to receive a first signal from a basestation and a second signal from a first communication device. Thecommunication device may include a determination circuit configured todetermine a first power level of the first signal and a second powerlevel of the second signal. The communication device may include acircuit configured to determine a power ratio of the first power levelto the second power level. The first signal and the second signal may bebased on a shared frequency. The communication device may be configuredto determine a third signal that comprises an interference parameterinformation based on the power ratio. Thus, the communication device,e.g. the circuit, may be configured to determine relative power levelsof signals that are based on a shared frequency. Further, thecommunication device may be configured to probe relative power levels ofsignals that are remote to another communication device.

Various aspects provide a base station that may include a transmitterconfigured to transmit signals based on a shared frequency. Further, thebase station may include a receiver configured to receive a connectionrequest signal based on the shared frequency from a first communicationdevice. Moreover, the base station may include a circuit configured todetermine a first signal based on the shared frequency that comprises arequest information of an interference parameter. Further, the circuitmay be configured to determine signals based on the interferenceparameter to transmit based on the shared frequency. Thus, the basestation may be configured to determine signals that are adapted to adistant interference situation. Further, the base station may beconfigured to flexibly target specific communication devices that aresuitable to determine an interference parameter of a distantinterference situation.

This disclosure provides a communication device that may include areceiver configured to receive signals from base stations. Thecommunication device may include a circuit configured to select a firstbase station from the base stations. A first signal may be transmittedfrom the first base station and a received first signal may be receivedfrom a second communication device. A second signal may be transmittedfrom a third communication device and a received second signal may bereceived from the second communication device. A parameter may be basedon a first power level of the received first signal and a second powerlevel of the received second signal. Further, the first base station maybe selected based on the parameter. Thus, the communication device maybe configured to select a base station that provides a strong signalrelative to the interference in the cell of the base station. Further,the communication device may be configured to increase the spectrumefficiency by exploiting frequencies of restricted spectrum.

Various aspects of this disclosure provide a communication system thatmay include a first communication device configured to determine anestimated signal state information. Further, the communication systemmay include a base station configured to transmit a first signal and aprojected signal and to determine the projected signal based on anestimated signal state information such that an energy of a shapedprojected signal is smaller than an energy of a shaped signal. Theestimated signal state information may be an estimate of a signal stateinformation based on the first signal and a received signal that isreceived by a receiver of a second communication device. The shapedprojected signal may be the projected signal received by the receiver ofthe second communication device and filtered by a filter of the secondcommunication device. The shaped signal may be the received signalfiltered by the filter of the second communication device. Thus, thecommunication system may be configured to effectively reduce the impactof interference signals on the second communication device. Further, thecommunication system may be configured to determine a reducedinterference signal independent from feedback of the secondcommunication device. Moreover, the communication system may beconfigured to flexibly adapt the reduction of the impact of interferencesignals to the filter of the second communication device. Further, thecommunication system may be configured to effectively determine anestimated signal state information exclusively by devices of the system.

FIG. 1 shows a schematic diagram of a scenario in which a mobile radiocommunication system 102 may be configured to operate as a LicensedShared Access (LSA) system. The mobile radio communication system 102may include an operations support system 104, an Operation,Administration and Maintenance (OAM) system 106 of a Mobile NetworkOperator (MNO), an incumbent base station 107, a first base station 110of the MNO and a second base station 111 of the MNO. The incumbent basestation 107 may be configured to provide radio frequency connections ina first radio frequency range. In an example, the first radio frequencyrange may be the frequency band between 2300 MHz and 2400 MHz or afrequency of the frequency band. Further, the operations support system104 may include an information repository that may store informationrelated to the availability of radio frequency resources of theincumbent base station 107 to base stations of the MNO. The informationrelated to the availability of radio frequency resources may include ageographical region and a first time period in which frequency resourcesof the incumbent base station 107 are available for a shared operation.

The second base station 111 of the MNO may be configured to provideradio frequency connections in the first radio frequency range in asecond time period of the first time period if the radio frequencyresources of the incumbent base station 107 are indicated as availablein the operations support system 104 in the second time period. Thefirst radio frequency range may be a shared frequency range that isshared between the incumbent base station 107 and the second basestation 111. If the second time period is expired the OAM system 106 maybe configured to instruct the second base station 111 to disable radiofrequency transmissions in the first radio frequency range.

In an example, the incumbent base station 107 may be configured toprovide radio frequency connections in a third radio frequency rangethat may be adjacent to the first radio frequency range or may have acommon range that is common to the first radio frequency range and thethird radio frequency range.

FIG. 2 shows a schematic drawing of a scenario in which a secondcommunication device 108, the first base station 110 and a sixthcommunication device 112 may be configured to connect via radiofrequency connections.

In an example, the scenario may be based on the mobile radiocommunication system 102.

In an example, the sixth communication device 112 may be the second basestation 111.

In an example, the second communication device 108 may be the incumbentbase station 107.

The second communication device 108 may be configured to provide radiofrequency connections in a first cell 202 in the first radio frequencyrange. The first base station 110 may be configured to provide radiofrequency connections in a second radio frequency range that isdifferent from the first radio frequency range. The sixth communicationdevice 112 may be configured to connect via radio frequency connectionsin a second cell 204 in the first radio frequency range. The second cell204 covers an area 206 that is covered by the first cell 202.

The first base station 110 may be configured to provide a first radiofrequency connection 208 to a first communication device 210 that may belocated in the area 206. The first communication device 210 may bereferenced as user equipment 1 (UE1). The sixth communication device 112may be configured to connect via a second radio frequency connection 212to a fourth communication device 214 that may be located in the area206. The fourth communication device 214 may be referenced as userequipment 4 (UE4).

In a scenario, the fourth communication device 214 may have been movedin the second cell 204 from outside of the area 206 to the area 206.Further, the second communication device 108 may be configured toprovide a third radio frequency connection 216 to a third communicationdevice 218 that may be located in the first cell 202. The thirdcommunication device 218 may be referenced as user equipment 3 (UE3).

The sixth communication device 112 may be configured to transmit a firstsample signal t₁ via a first transmission path 220. The thirdcommunication device 218 may be configured to transmit a second samplesignal t₂ via a second transmission path 222. The fourth communicationdevice 214 may be configured to transmit a third sample signal t₃ via athird transmission path 224.

The sixth communication device 112 may be configured to transmit signalsbased on a Multiple Input Multiple Output (MIMO) technology. The sixthcommunication device 112 may be configured to transmit the first samplesignal t₁ based on a second plurality of antennas that includes N_(6,T)antennas and a first precoding vector q₁ of dimension N_(6,T).

The third communication device 218 may be configured to transmit signalsbased on the MIMO technology. The third communication device 218 may beconfigured to transmit the second sample signal t₂ based on a fourthplurality of antennas that includes N_(3,T) antennas and a secondprecoding vector q₂ of dimension N_(3,T).

The fourth communication device 214 may be configured to transmitsignals based on the MIMO technology. The fourth communication device214 may be configured to transmit the third sample signal t₃ based on athird plurality of antennas that includes N_(4,T) antennas and a thirdprecoding vector q₃ of dimension N_(4,T).

The first communication device 210 may be configured to receive signalsbased on the first radio frequency range from which a received firstsample signal r₁ may be shaped based on the first transmission path 220,from which a received second sample signal r₂ may be shaped based on thesecond transmission path 222 and from which a received third samplesignal r₃ may be shaped based on the third transmission path 224. Thereceived first sample signal r₁, the received second sample signal r₂and the received third sample signal r₃ may be received based on thefirst sample signal t₁, the second sample signal t₂ and the third samplesignal t₃, respectively.

The received first signal r₁ may be related with the first sample signalbased on a first signal state operator H₁ by a formula (1):

r ₁ =H ₁ t ₁.  (1)

The first sample signal t₁ may be based on signal components that may betransmitted based on the second plurality of antennas. The first signalstate operator H₁ may be a matrix. Further, the first signal stateoperator H₁ may correspond to a linear transfer function that isassociated with the first transmission path 220.

The received second signal r₂ may be related with the second samplesignal t₂ based on a second signal state operator H₂ by a formula (2):

r ₂ =H ₂ t ₂.  (2)

The second sample signal t₂ may be based on at least one signalcomponent that may be transmitted based on at least one antenna of thethird communication device 218. The second signal state operator H₂ maybe a matrix. Further, the second signal state operator H₂ may correspondto a linear transfer function that is associated with the secondtransmission path 222.

The received third signal r₃ may be related with the third sample signalt₃ based on a third signal state operator H₃ by a formula (3):

r ₃ =H ₃ t ₃.  (3)

The third sample signal t₃ may be based on signal components that may betransmitted based on antennas of the third plurality of antennas of thefourth communication device 218. The third signal state operator H₃ maybe a matrix. Further, the third signal state operator H₃ may correspondto a linear transfer function that is associated with the thirdtransmission path 224.

A received aggregate signal r that is received by the firstcommunication device 210 may be related with the sample signals t₁, t₂and t₃ that are scalars based on the first precoding vector q₁, thesecond precoding vector q₂, the third precoding vector q₃, the firstsignal state operator H₁, the second signal state operator H₃, the thirdsignal state operator H₃ and additive white Gaussian noise n₁ by aformula (4):

r=H ₁ q ₁ t ₁ +H ₂ q ₂ t ₂ +H ₃ q ₃ t ₃ +n ₁.  (4)

Further, the second communication device 108 may be configured toreceive signals based on the first radio frequency range from which areceived first interference signal w₁ may be shaped based on atransmission path between the sixth communication device 112 and thesecond communication device 108, from which a received second datasignal w₂ may be shaped based on a second transmission path between thethird communication device 218 and the second communication device 108and from which a received third interference signal w₃ may be shapedbased on a transmission path between the fourth communication device 214and the second communication device 108. The first interference signalw₁, the second data signal w₂ and the third interference signal w₃ maybe based on the first sample signal t₁, the second sample signal t₂ andthe third sample signal t₃, respectively.

The first interference signal w₁ may be related with the first samplesignal t₁ based on a first signal state matrix K₁ that may be based on asignal state information by a formula (5):

w ₁ =K ₁ t ₁.  (5)

The second data signal w₂ may be related with the second sample signalt₂ based on a second signal state matrix K₂ that may be based on asecond signal state information by a formula (6):

w ₂ =K ₂ t ₂.  (6)

The third interference signal w₃ may be related with the third samplesignal t₃ based on a third signal state matrix K₃ that may be based on athird signal state information by a formula (7):

w ₃ =K ₃ t ₃.  (7)

The second communication device 108 may be configured to receive signalsbased on the MIMO technology. The second communication device 108 may beconfigured to receive the first interference signal w₁, the second datavector w₂ and the third interference vector w₃ based on a firstplurality of antennas that includes N_(2,R) antennas.

A received aggregate signal w that is received by the secondcommunication device 108 may be related with the sample signals t₁, t₂and t₃ that are scalars based on the first precoding vector q₁, thesecond precoding vector q₂, the third precoding vector q₃, the firstsignal state matrix K₁, the second signal state matrix K₂, the thirdsignal state matrix K₃ and additive white Gaussian noise n₂ by a formula(8):

w ₁ =K ₁ q ₁ t ₁ +K ₂ q ₂ t ₂ +K ₃ q ₃ t ₃ +n ₂.  (8)

The first signal state operator H₁ may be an estimate of the firstsignal state matrix K₁. The second signal state operator H₂ may be anestimate of the second signal state matrix K₂. The third signal stateoperator H₃ may be an estimate of the third signal state matrix K₃.

In an example, the first communication device 210 may be configured toprovide the received first sample signal r₁, the received second samplesignal r₂ and the received third sample signal r₃ to the sixthcommunication device 112 via the first base station 110.

In an example, the sixth communication device 112 may be configured toselect the first communication device 210 such that features of thefirst transmission path 220 and the transmission path between the sixthcommunication device 112 and the second communication device 108 aresimilar. Further, features of the second transmission path 222 and thetransmission path between the third communication device 218 and thesecond communication device 108 may be similar. Moreover, features ofthe third transmission path 224 and the transmission path between thefourth communication device 214 and the second communication device 108may be similar. Thus, the sixth communication device 112 may beconfigured to determine a reliable data basis.

The received first sample signal r₁ may be received at a first time, thereceived second sample signal r₂ may be received at a second time andthe received third sample signal r₃ may be received at a third time. Thefirst time, the second time and the third time may be times of thesecond time period. In an example, the first time, the second time andthe third time may be different times, respectively. Thus, the firstcommunication device may be configured to receive the most currentsignals as data basis.

In an example, the first communication device 210 may be configured totransmit signals to the sixth communication device 112 and receivesignals from the sixth communication device 112 via at least one of timedivision multiplexing and frequency division multiplexing. The fourthcommunication device 214 may be configured to transmit signals to thesixth communication device 112 and receive signals from the sixthcommunication device 112 via at least one of time division multiplexingand frequency division multiplexing. Thus, the fourth communicationdevice may be configured to connect to the communication devices in aflexible manner.

In an example, a communication system may include the firstcommunication device 210 and the second base station 111.

FIG. 3 shows a schematic diagram of a communication device 302 that mayinclude a transmitter 304 and a circuit 306. The circuit 306 may beconnected with the transmitter 304.

The communication device 302 may be the sixth communication device 112.

The transmitter 304 may be configured to transmit the first samplesignal t₁.

The circuit may be configured to determine an estimated signal stateinformation. The estimated signal state information may be an estimateof the signal state information. The estimated signal state informationmay be based on a first operator G₁.

The circuit 306 may be configured to determine a projected first signalp₁ based on the estimated signal state information such that an energyof a shaped projected first signal u₁ is smaller than an energy of ashaped first signal s₁. The circuit 306 may be configured to determinethe shaped first signal s₁ based on the first sample signal t₁, theestimated signal state information and a filter of the secondcommunication device 108. The shaped first signal s₁ may be related withthe first sample signal t₁ based on the first signal state operator G₁by a formula (9):

s ₁ =G ₁ t ₁.  (9)

The circuit 306 may be configured to determine the shaped projectedfirst signal u₁ based on the projected first signal p₁, the estimatedsignal state information and the filter of the second communicationdevice 108. The shaped projected first signal u₁ may be related with theprojected first signal p₁ based on the first operator G₁ by a formula(10):

u ₁ =G ₁ p ₁.  (10)

The transmitter 304 may be configured to transmit the projected firstsignal p₁.

Thus, the communication device 302 may be configured to effectivelyreduce interference energies of interference signals that interfere withsignals that are transmitted from a third communication device andreceived from the second communication device.

In an example, the circuit 306 may be a baseband circuit.

In an example, the second communication device 108 may be configured toreceive the energy of the shaped projected first signal u₁ and theenergy of the shaped first signal s₁ in a predefined time period.

In an example, the energy of the shaped projected first signal u₁ may bean estimated energy of the shaped projected first signal u₁. The energyof the shaped first signal s₁ may be an estimated energy of the shapedfirst signal s₁.

In an example, the circuit 306 may be configured to estimate theestimated energy of the shaped projected first signal u₁ and theestimated energy of the shaped first signal s₁ based on the estimatedsignal state information and the filter of the second communicationdevice 108.

In an example, the circuit 306 may be configured to determine theestimated signal state information based on the first sample signal t₁and the received first sample signal r₁. The estimated signal stateinformation may be the first signal state matrix H₁.

In an example, the circuit 306 may be configured to receive theestimated signal state information from the first communication device210.

In an example, the circuit 306 may be configured to determine theestimated signal state information based on a pilot signal that isincluded in the first sample signal t₁ and the received first samplesignal r₁. Thus, the circuit 306 may be configured to reliably determinethe estimated signal state information.

The circuit 306 may be configured to determine the projected firstsignal p₁ based on a first vector v₁ of input signals. The first vectorv₁ may be based on a first plurality of input signals. The components ofthe first vector v₁ may be input signals of the first plurality of inputsignals, respectively. The input signals of the first plurality of inputsignals may be transmitted by the antennas of the second plurality ofantennas, respectively. Thus, the circuit 306 may be configured toefficiently determine the projected signal based on a multiple inputtechnology.

The circuit 306 may be configured to determine the projected firstsignal p₁ based on a second vector v₂ of input signals. The secondvector v₂ may be based on a second plurality of input signals thatcorrespond to the antennas of the second plurality of antennas. Thecomponents of the second vector v₂ may be input signals of the secondplurality of input signals that are transmitted by the antennas of thesecond plurality of antennas, respectively.

The circuit 306 may be configured to determine the projected firstsignal p₁ based on a third vector v₃ of output signals. The third vectorv₃ may be based on a third plurality of output signals that are receivedfrom the second communication device 108 based on antennas of the firstplurality of antennas of the second communication device 108,respectively. The third plurality of output signals may be receivedbased on the projected first signal p₁. Thus, the circuit 306 may beconfigured to efficiently determine projected signals based on amultiple output technology.

The circuit 306 may be configured to determine the projected firstsignal p₁ based on a fourth vector v₄ of output signals. The fourthvector v₄ may be based on a fourth plurality of output signals that arereceived from the second communication device 108 based on the antennasof the first plurality of antennas, respectively. The fourth pluralityof output signals may be received based on the first sample signal t₁.

The circuit 306 may be configured to determine an estimated linearprocess based on the estimated signal state information such that theestimated linear process is an estimate of a linear process that isbased on the signal state information.

In an example, the filter of the second communication device 108 may bean identical pass filter.

The estimated linear process may be the first signal state operator H₁.The circuit 306 may be configured to determine the first signal stateoperator H₁ based on the first sample signal t₁ and the received firstsample signal r₁ based on a formula (11):

r ₁ =H ₁ t ₁.  (11)

The circuit 306 may be configured to determine a first scalar product X₁based on the first vector v₁ and the third vector v₃ by a formula (12):

X ₁ =v ₁ ·v ₃.  (12)

The circuit 306 may be configured to determine a second scalar productX₂ based on the second vector v₂ and the fourth vector v₄ by a formula(13):

X ₂ =v ₂ ·v ₄.  (13)

The circuit 306 may be configured to determine the first vector v₁ suchthat a first absolute value of the first scalar product X₁ is smallerthan a second absolute value of the second scalar product X₂. Thus, thecircuit 306 may be configured to effectively determine projected signalsthat reduce interference energies of received and filtered projectedsignals relative to the interference energies of unprojected signals.

In an example, the circuit 306 may be configured to determine the firstvector v₁ such that the first scalar product X₁ is zero.

In an example, the sixth communication device 112 may provide radiofrequency connections in the first radio frequency range as a downlink.Thus, an interference of signals with signals of a third communicationdevice that transmits in the same frequency range can flexibly andefficiently be reduced.

In an example, the filter of the second communication device 108 may bebased on maximal ratio combining.

In an example, the filter of the second communication device 108 may bea maximum likelihood filter.

The filter of the second communication device 108 may be configured tofilter based on a channel state information of the third radio frequencyconnection 216. The channel state information may be a linear transferfunction of a signal that is transmitted from the third communicationdevice 218 and a received signal that is received from the secondcommunication device 108. The second signal state information may be anestimate of the channel state information that may be based on thetransmission of signals different from the second sample signal t₂.

The circuit may be configured to determine an estimated second signalstate information. The estimated second signal state information may bean estimate of the second signal state information. The second signalstate information may be based on a signal that is transmitted from thethird communication device 218 and a received signal that is receivedfrom the second communication device 108. Thus, the circuit 306 may beconfigured to flexibly determine the projected signal based on thefilter of the second communication device 108.

In an example, the signal that is transmitted from the thirdcommunication device 218 may be the second sample signal t₂. Thereceived signal that is received from the second communication device108 may be the second interference signal w₂.

The circuit 306 may be configured to determine the estimated secondsignal state information based on the second sample signal t₂ and thereceived second sample signal r₂.

In an example, the estimated second signal state information may be thesecond signal state operator H₂.

In an example, the circuit 306 may be configured to determine theestimated second signal state information based on a pilot signal thatis included in the second sample signal t₂ and the received secondsample signal r₂. Thus, the circuit 306 may be configured to reliablydetermine the estimated second signal state information.

In an example, the circuit 306 may be configured to receive theestimated second signal state information from the first communicationdevice 210.

The circuit 306 may be configured to determine the estimated linearprocess based on the estimated signal state information and theestimated second signal state information.

The circuit 306 may be configured to determine the second signal stateoperator H₂ based on the second sample signal t₂ and the received secondsample signal r₂ based on a formula (14):

r ₂ =H ₂ t ₂.  (14)

The circuit 306 may be configured to determine an estimated linearprocess matrix M₁ of the estimated linear process based on the firstsignal state operator H₁, the second signal state operator H₂ and aHermitian conjugate operator (⋅)^(H) by a formula (15):

M ₁ =H ₂ ^(H) H ₁.  (15)

The circuit 306 may be configured to determine a spectral decompositionof the second vector v₂ based on eigenvectors of the estimated linearprocess matrix M₁.

If the second vector v₂ is an eigenvector of the estimated linearprocess matrix M₁: The circuit 306 may be configured to determine thefirst vector v₁ such that the first vector v₁ is a sum of eigenvectorsof the estimated linear process matrix M₁ to eigenvalues of theestimated linear process matrix M₁ that are smaller than an eigenvalueof the second vector v₂ of the estimated linear process matrix M₁. Thus,the circuit 306 may be configured to determine the projected firstsignal p₁ in a simple and reliable manner.

If the second vector v₂ is a sum of eigenvectors of the estimated linearprocess matrix M₁: The circuit 306 may be configured to determine thefirst vector v₁ such that the first vector v₁ is a sum of eigenvectorsof the estimated linear process matrix M₁ to eigenvalues of theestimated linear process matrix M₁ that are smaller than a smallesteigenvalue of the eigenvalues of the sum of eigenvectors of theestimated linear process matrix M₁. Thus, the circuit 306 may beconfigured to determine the projected first signal p₁ in a simple andreliable manner.

In an example, if the second vector v₂ is an eigenvector of theestimated linear process matrix M₁: The circuit 306 may be configured todetermine the first vector v₁ such that the first vector v₁ is aneigenvector of the estimated linear process matrix M₁ to an eigenvalueof the estimated linear process matrix M₁ that is smaller than aneigenvalue of the second vector v₂ of the estimated linear processmatrix M₁. Thus, the circuit 306 may be configured to determine theprojected first signal p₁ in a simple and reliable manner.

If the second vector v₂ is a sum of eigenvectors of the estimated linearprocess matrix M₁: The circuit 306 may be configured to determine thefirst vector v₁ such that the first vector v₁ is an eigenvector of theestimated linear process matrix M₁ to an eigenvalue of the estimatedlinear process matrix M₁ that is smaller than eigenvalues of the sum ofeigenvectors to the estimated linear process matrix M₁. Thus, thecircuit 306 may be configured to determine the projected first signal p₁in a simple and reliable manner.

In an example, the circuit 306 may be configured to determine a firstprojector P₁ such that a projection of the first sample signal t₁ basedon the first projector P₁ is the projected first signal p₁.

In an example, the first projector P₁ may be unitary.

In an example, the circuit 306 may be configured to determine the firstprojector P₁ based on a first matrix that is orthogonal to the estimatedlinear process matrix M₁. The first matrix may be configured to projectvectors to a kernel space of the estimated linear process matrix M₁. Theestimated linear process matrix M₁ may be configured to project vectorsof the kernel space to a zero vector.

In an example, the circuit 306 may be configured to determine the firstprojector P₁ based on two antennas of the second plurality of antennas,two antennas of the first plurality of antennas, the estimated linearprocess matrix M₁ and a transpose matrix M₁ ^(T) by a formula (16):

$\begin{matrix}{{P_{1} = {\begin{pmatrix}0 & {- 1} \\1 & 0\end{pmatrix}M_{1}^{T}}}.} & (16)\end{matrix}$

In an example, the circuit 306 may be configured to determine the firstprojector P₁ based on two antennas of the second plurality of antennas,two antennas of the first plurality of antennas, a permutation matrix A,that may be determined by a formula (17):

$\begin{matrix}{{A = \begin{pmatrix}0 & {- 1} \\1 & 0\end{pmatrix}},} & (17)\end{matrix}$

and the estimated linear process matrix M₁ by a formula (18):

$\begin{matrix}{{P_{1} = \frac{A \cdot M_{1}^{T}}{{A \cdot M_{1}^{T}}}}.} & (18)\end{matrix}$

In case of four antennas of the first plurality and four antennas of thesecond plurality the circuit 306 is configured to determine the firstprojector P₁ based on a second matrix B, that may be determined based ona zero matrix Z₀ by a formula (19):

$\begin{matrix}{{B = \begin{pmatrix}A & Z_{0} \\Z_{0} & A\end{pmatrix}},} & (19)\end{matrix}$

and the estimated linear process matrix M₁ by a formula (20):

$\begin{matrix}{{P_{1} = \frac{B \cdot M_{1}^{T}}{{B \cdot M_{1}^{T}}}}.} & (20)\end{matrix}$

In case of a complex matrix M₁ the transpose matrix M₁ ^(T) may bereplaced by a Hermitian conjugate matrix M₁ ^(H).

In an example, the circuit 306 may be configured to provide the firstprojector P₁ to the fourth communication device 214.

In an example, the communication device may be a base station.

In an example, the circuit 306 may be configured to select the firstcommunication device 210 from a plurality of communication devices thatare located in the area 206 such that a distance from the firstcommunication device 210 to the second communication device 108 is asmallest from the distances of the communication devices of theplurality of communication devices. Thus, an the circuit may beconfigured to reliably reduce an interference of signals of thecommunication device with signals from other communication devices inthe same frequency range.

In an example, the sixth communication device may be configured todetermine the estimated signal state information based on a receivedsample signal based on a sample signal that is transmitted from thefirst communication device. The received sample signal may include apilot signal.

In an example, the received first sample signal r₁ may be the receivedfirst sample signal t₁.

In an example, the received second sample signal r₂ may be the receivedsecond sample signal t₂.

In an example, the first communication device may be configured totransmit a sample signal based on a time division multiplexingtechnology. The first communication device may be configured to transmitpilot signals in time periods in which no pilot signal is transmittedfrom the third communication device. Thus, the sixth communicationdevice may be configured to efficiently determine the estimated signalstate information based on channel reciprocity. Further, the firstcommunication device may be configured to transmit null subcarriersbased on subcarriers that are transmitted by the third communicationdevice and include pilot signals. Thus, the first communication devicemay be configured to increase the accuracy of determined channelparameters.

In an example, the sixth communication device may be configured totransmit sample signal based on a frequency division multiplexingtechnology. The sixth communication device may be configured to transmitpilot signals based on subcarriers based on which null subcarriers aretransmitted from the third communication device. Thus, the firstcommunication device may be configured to efficiently determine theestimated signal state information. Further, the sixth communicationdevice may be configured to transmit null subcarriers based on whichpilot signals are transmitted by the third communication device. Thesixth communication device may be configured to transmit precodedsignals instead of null subcarriers. Thus, the sixth communicationdevice may be configured to increase the data rate.

In an example, a communication system may include a control device, thesixth communication device 112 and the second communication device 108.The sixth communication device 112 and the second communication device108 may be registered in the control device to transmit based on theshared frequency range in a shared area. The shared area may be the area206. The shared frequency range may be a shared frequency.

In an example, aspects of the sixth communication device 112 based onFIG. 2 may be aspects of the communication device 302.

In an example, the first communication device 302 based FIG. 3 may bebased on the communication devices of FIG. 1 and FIG. 2.

Aspects of the communication device 302 of FIG. 3 may be combined withaspects of the scenarios based on FIG. 1 and FIG. 2. In an example, thecommunication device 302 of FIG. 3 may be based on the communicationdevices based on FIG. 1 and FIG. 2.

FIG. 4 shows a schematic diagram of a communication device 402 that mayinclude a transmitter 404 and a circuit 406. The circuit 406 may beconnected with the transmitter 404.

The circuit 406 may be configured to determine an estimated third signalstate information. The estimated third signal state information may bean estimate of the third signal state information. The third signalstate information may be based on the third sample signal t₃ that istransmitted by the fourth communication device 214 and the receivedthird interference signal that is received from the second communicationdevice 108. The estimated third signal state information may be based ona second operator G₂.

The circuit 406 may be configured to determine a second projectioninformation such that an energy of a shaped projected second signal u₂is smaller than an energy of a shaped second signal s₂. The circuit 406may be configured to determine the shaped second signal s₂ based on theestimated third signal state information and the filter of the secondcommunication device 108. The shaped second signal s₂ may be relatedwith a second signal a₂ based on the second operator G₂ by a formula(21):

s ₂ =G ₂ a ₂.  (21)

The circuit 406 may be configured to determine a projected second signalp₂ that may be projected based on the second projection information andthe second signal a₂. The second projection information may be a secondprojector P₂. The circuit 406 may be configured to determine the shapedprojected second signal u₂ based on the projected second signal p₂, theestimated third signal state information and the filter of the secondcommunication device 108. The shaped projected second signal u₂ may berelated with the projected second signal p₂ based on the second operatorG₂ by a formula (22):

u ₂ =G ₂ p ₂  (22)

Thus, the circuit 406 may be configured to effectively reduceinterference energies of interference signals that interfere withsignals that are transmitted from a third communication device andreceived from the second communication device.

In an example, the circuit 406 may be a baseband circuit.

In an example, the fourth communication device 214 may be configured totransmit the second signal a₂ and/or the projected second signal p₂.

In an example, the second signal a₂ may be the third sample signal t₃.

In an example, the second communication device 108 may be configured toreceive the energy of the shaped projected second signal u₂ and theenergy of the shaped second signal s₂ in a predefined time period.

In an example, the energy of the shaped projected second signal u₂ maybe an estimated energy of the shaped projected second signal u₂. Theenergy of the shaped second signal s₂ may be an estimated energy of theshaped second signal s₂.

In an example, the circuit 406 may be configured to estimate theestimated energy of the shaped projected second signal u₂ and theestimated energy of the shaped second signal s₂ based on the estimatedsignal state information and the filter of the second communicationdevice 108.

In an example, the transmitter 404 may be configured to transmit thesecond projection information to the fourth communication device 214.

In an example, the circuit 406 may be configured to receive theestimated third signal state information from the first communicationdevice 210.

In an example, the circuit 406 may be configured to determine theestimated third signal state information based on the third samplesignal t₃ and the received third sample signal r₃. The estimated thirdsignal state information may be the third signal state matrix H₃.

In an example, the circuit 406 may be configured to determine theestimated third signal state information based on a pilot signal that isincluded in the third sample signal t₃ and the received third samplesignal r₃. Thus, the circuit 406 may be configured to reliably determinethe estimated signal state information.

The circuit 406 may be configured to determine the projected secondsignal p₂ based on a fifth vector v₅ of input signals. The fifth vectorv₅ may be based on a fifth plurality of input signals that correspond toantennas of the third plurality of antennas of the fourth communicationdevice 214. The components of the fifth vector v₅ may be input signalsof the fifth plurality of input signals, respectively. The input signalsof the fifth plurality of input signals may be transmitted by theantennas of the third plurality of antennas, respectively. Thus, thecircuit 406 may be configured to efficiently determine signal projectorsbased on a multiple input technology.

The circuit 406 may be configured to determine the projected secondsignal p₂ based on a sixth vector v₆ of input signals. The sixth vectorv₆ may be based on a sixth plurality of input signals that correspond tothe antennas of the third plurality of antennas. The components of thesixth vector v₆ may be input signals of the sixth plurality of inputsignals that are transmitted by the antennas of the third plurality ofantennas, respectively. Thus, the circuit 406 may be configured toefficiently determine signal projectors based on a multiple inputtechnology.

The circuit 406 may be configured to determine the projected secondsignal p₂ based on a seventh vector v₇ of output signals. The seventhvector v₇ may be based on a seventh plurality of output signals that arereceived from the second communication device 108. The seventh pluralityof output signals may be received based on the projected second signalp₂. Thus, the circuit 406 may be configured to efficiently determinesignal projectors based on a multiple output technology.

The circuit 406 may be configured to determine the projected secondsignal p₂ based on an eighth vector v₈ of output signals. The eighthvector v₈ may be based on an eighth plurality of output signals that arereceived from the second communication device 108. The eighth pluralityof output signals may be received based on the second signal a₂. Thus,the circuit 406 may be configured to efficiently determine signalprojectors based on a multiple output technology.

The circuit 406 may be configured to determine a third scalar product X₃based on the fifth vector v₅ and the seventh vector v₇ by a formula(23):

X ₃ =v ₅ ·v ₇.  (23)

The circuit 406 may be configured to determine a fourth scalar productX₄ based on the sixth vector v₆ and the eighth vector v₈ by a formula(24):

X ₄ =v ₆ ·v ₈.  (24)

The circuit 406 may be configured to determine the fifth vector v₅ suchthat a third absolute value of the third scalar product X₃ is smallerthan a fourth absolute value of the fourth scalar product X₄. Thus, thecircuit 406 may be configured to effectively determine signal projectorsthat reduce interference energies of received and filtered projectedsignals relative to the interference energies of unprojected signals.

In an example, the circuit 406 may be configured to determine the fifthvector v₅ such that the third scalar product X₃ is zero.

The circuit 406 may be configured to determine an estimated secondlinear process based on the estimated second signal state informationand the estimated third signal state information. The circuit 306 may beconfigured to determine the third signal state operator H₃ based on thethird sample signal t₃ and the received third sample signal r₃ based ona formula (25):

r ₃ =H ₃ t ₃  (25)

In an example, the estimated third signal state information may be thethird signal state operator H₃.

The circuit 406 may be configured to determine a second estimated linearprocess matrix M₂ of the estimated second linear process based on thesecond signal state operator H₂, the third signal state operator H₃ anda Hermitian conjugate operator (⋅)^(H) by a formula (26):

M ₂ =H ₂ ^(H) H ₃.  (26)

The circuit 406 may be configured to determine a spectral decompositionof the sixth vector v₆ based on eigenvectors of the second estimatedlinear process matrix M₂.

If the sixth vector v₆ is an eigenvector of the second estimated linearprocess matrix M₂: The circuit 406 may be configured to determine thefifth vector v₅ such that the fifth vector v₅ is a sum of eigenvectorsof the second estimated linear process matrix M₂ to eigenvalues of thesecond estimated linear process matrix M₂ that are smaller than aneigenvalue of the sixth vector v₆ of the second estimated linear processmatrix M₂. Thus, the circuit 406 may be configured to determine thesecond projection information in a simple and reliable manner.

If the sixth vector v₆ is a sum of eigenvectors of the second estimatedlinear process matrix M₂: The circuit 406 may be configured to determinethe fifth vector v₅ such that the fifth vector v₅ is a sum ofeigenvectors of the second estimated linear process matrix M₂ toeigenvalues of the second estimated linear process matrix M₂ that aresmaller than a smallest eigenvalue of the eigenvalues of the sum ofeigenvectors of the second estimated linear process matrix M₂. Thus, thecircuit 406 may be configured to determine the second projectioninformation in a simple and reliable manner.

In an example, the second projector P₂ may be unitary.

In an example, the circuit 406 may be configured to determine the secondprojector P₂ based on a second matrix that is orthogonal to the secondestimated linear process matrix M₂. The second matrix may be configuredto project vectors to a kernel space of the second estimated linearprocess matrix M₂. The second estimated linear process matrix M₂ may beconfigured to project vectors of the kernel space to a zero vector.

In an example, the circuit 406 may be configured to determine the secondprojector P₂ based on two antennas of the third plurality of antennas,two antennas of the first plurality of antennas, the second estimatedlinear process matrix M₂ and a transpose matrix M₂ ^(T) by a formula(27):

$\begin{matrix}{{P_{2} = {\begin{pmatrix}0 & {- 1} \\1 & 0\end{pmatrix}M_{2}^{T}}}.} & (27)\end{matrix}$

In case of a real matrix M₂ the Hermitian conjugation is a transpose ofthe second estimated linear process matrix M₂.

In an example, the circuit 406 may be configured to determine the secondprojector P₂ based on two antennas of the third plurality of antennas,two antennas of the first plurality of antennas, the permutation matrixA, the second estimated linear process matrix M₂ and the transposematrix M₂ ^(T) by a formula (28):

$\begin{matrix}{P_{2} = {\frac{A \cdot M_{2}^{T}}{{A \cdot M_{2}^{T}}}.}} & (28)\end{matrix}$

In case of four antennas of the third plurality and four antennas of thesecond plurality the circuit 406 is configured to determine the secondprojector P₂ based on the second matrix B, the second estimated linearprocess matrix M₂ and a transpose matrix M₂ ^(T) by a formula (29):

$\begin{matrix}{{P_{2} = \frac{B \cdot M_{2}^{T}}{{B \cdot M_{2}^{T}}}}.} & (29)\end{matrix}$

In case of a complex matrix M₂ the transpose matrix M₂ ^(T) may bereplaced by a Hermitian conjugate matrix M₂ ^(H).

In an example, the first communication device may be configured todetermine the estimated second signal state information based on areceived sample signal based on a sample signal that is transmitted fromthe first communication device. The received sample signal may include apilot signal.

In an example, the first communication device may be configured totransmit the sample signal based on a time division multiplexingtechnology. The first communication device may be configured to transmitpilot signals in time periods in which no pilot signal is transmittedfrom the third communication device. Thus, the first communicationdevice may be configured to efficiently determine the estimated secondsignal state information based on channel reciprocity. Further, thethird communication device may be configured to transmit nullsubcarriers based on subcarriers that are transmitted by the firstcommunication device and include pilot signals. Thus, the thirdcommunication device may be configured to increase the accuracy ofdetermined channel parameters.

In an example, the received third sample signal r₃ may be the receivedthird sample signal t₃.

In an example, the third communication device may be configured totransmit sample signal based on a frequency division multiplexingtechnology. The third communication device may be configured to transmitpilot signals based on subcarriers based on which null subcarriers aretransmitted from the sixth communication device. Thus, the firstcommunication device may be configured to efficiently determine theestimated signal state information. Further, the third communicationdevice may be configured to transmit null subcarriers based on whichpilot signals are transmitted by the sixth communication device. Thethird communication device may be configured to transmit precodedsignals instead of null subcarriers. Thus, the third communicationdevice may be configured to increase the data rate.

In an example, aspects of the communication device 302 based on FIG. 3may be aspects of the communication device 402. The circuit 406 may bebased on the circuit 306.

In an example, the communication device 402 of FIG. 4 may be based onthe communication devices based on FIG. 1, FIG. 2 and FIG. 3.

It should be noted that aspects of the communication device 402 of FIG.4 may be combined with aspects of the communication device based on FIG.3. Aspects of the communication device 402 of FIG. 4 may be combinedwith aspects of the scenarios based on FIG. 1 and FIG. 2.

FIG. 5 shows a schematic diagram of a scenario of a base station 502, afirst communication device 504 (UE1), a second communication device 514(UE2), a third communication device 508 (UE3), a fourth communicationdevice 506 (UE4), a fifth communication device 510 (UE5) and a sixthcommunication device 512 (UE6). The sixth communication device 512 maybe configured to transmit and receive radio frequency signals in a firstradio frequency range in a first cell 516. Further, the base station 502may be configured to provide radio frequency connections in a secondcell 518 in a second radio frequency range. The second cell 518 maycover an area 520 that may be covered by the first cell 516. Further,the base station 502 may be configured to provide a first radiofrequency connection to the first communication device 504 and a secondradio frequency connection to the fifth communication device 510.Moreover, the second communication device 514 may be configured toprovide a third radio frequency connection 515 to the thirdcommunication device 508.

The sixth communication device 512 may be configured to transmit a firstsignal via a first transmission path 522. The third communication device508 may be configured to transmit a second signal via a secondtransmission path 524 to the first communication device 504. The fourthcommunication device 506 may be configured to transmit a third signalvia a third transmission path 526.

The sixth communication device 512 may be configured to transmit afourth signal via a fourth transmission path 528. The thirdcommunication device 508 may be configured to transmit a fifth signalvia a fifth transmission path 530. The fourth communication device 506may be configured to transmit a sixth signal via a sixth transmissionpath 532.

The first communication device 504 may be configured to receive radiofrequency signals based on the first radio frequency range from which areceived first signal may be shaped by the first transmission path 522,from which a received second signal may be shaped by the secondtransmission path 524 and from which a received third signal may beshaped by the third transmission path 526.

The fifth communication device 510 may be configured to receive radiofrequency signals based on the first radio frequency range from which areceived fourth signal may be shaped by the fourth transmission path528, from which a received fifth signal may be shaped by the fifthtransmission path 530 and from which a received sixth signal may beshaped by the sixth transmission path 532.

In an example, aspects of the communication device 402 based on FIG. 4may be aspects of the sixth communication device 512.

It should be noted that aspects of the scenario of FIG. 5 may becombined with aspects of the communication devices based on FIG. 3 andFIG. 4. Aspects of the scenario of FIG. 5 may be combined with aspectsof the scenarios based on FIG. 1 and FIG. 2.

FIG. 6 shows a schematic diagram of a communication device 602 that mayinclude a transmitter 604 and a circuit 606. The circuit 606 may beconnected with the transmitter 604. Features of FIG. 6 that may besimilar to features based on FIG. 5 may be referenced alike.

The circuit 606 may be configured to determine the estimated signalstate information based on an interpolation of the received first signaland the received fourth signal. Thus, the circuit 606 may be configuredto accurately determine a data basis for the determination of theprojected signals.

The circuit 606 may be configured to determine the estimated secondsignal state information based on an interpolation of the receivedsecond signal and the received fifth signal.

The circuit 606 may be configured to determine the projected signal p₁based on a first projection information.

The circuit 606 may be configured to determine an interpolated firstsignal based on the first signal and the fourth signal.

The circuit 606 may be configured to determine an interpolated secondsignal based on the second signal and the fifth signal.

A shaped interpolated first signal may be shaped based on theinterpolated first signal in correspondence to the estimated linearprocess.

The circuit 606 may be configured to determine a projected interpolatedfirst signal based on the interpolated first signal and the firstprojection information.

A shaped projected interpolated first signal may be shaped based on theprojected interpolated first signal in correspondence to the estimatedlinear process.

A shaped interpolated second signal may be shaped based on theinterpolated second signal in correspondence to the estimated linearprocess.

The circuit 606 may be configured to determine a projected interpolatedsecond signal based on the interpolated second signal and the firstprojection information.

A shaped projected interpolated second signal may be shaped based on theprojected interpolated second signal in correspondence to the estimatedlinear process.

The circuit 606 may be configured to determine an interpolated shapedinterpolated first signal based on the shaped interpolated first signaland the shaped interpolated second signal.

The circuit 606 may be configured to determine an interpolated shapedprojected interpolated first signal based on the shaped projectedinterpolated first signal and the shaped projected interpolated secondsignal.

The circuit 606 may be configured to determine the first projectioninformation based on the estimated linear process, the interpolatedfirst signal and the interpolated second signal such that a fifthabsolute value of a fifth scalar product of the projected interpolatedfirst signal and the interpolated shaped projected interpolated firstsignal is smaller than a sixth absolute value of a sixth scalar productof the interpolated first signal and the interpolated shapedinterpolated first signal. Thus, the circuit 606 may be configured toeffectively reduce the interference of downlink signals with signalsthat the second communication device 108 receives from othercommunication devices.

In an example, the circuit 606 may be a baseband circuit.

In an example, the circuit 606 may be configured to determine theestimated third signal state information based on weight factors thatare associated with the received first signal, the received fourthsignal, the received second signal and the received fifth signal basedon distances of the first communication device 504 and the fifthcommunication device 510 to the second communication device 514. Theweight of the weight factor decreases based on an increase of thedistance of the respective communication device to the secondcommunication device 510. Thus, the circuit 606 may be configured toincrease the accuracy of the data basis for the determination of theprojected signals.

In an example, the transmitter 604 may be configured to transmit signalsbased on at least one of time division multiplexing and frequencydivision multiplexing. The fourth communication device 506 may beconfigured to receive signals and transmit signals based on at least oneof time division multiplexing and frequency division multiplexing.

In an example, the circuit 606 may be configured to transmit the fourthsignal in a time period that follows the transmissions of the firstsignal. Thus, the first circuit 606 may be configured to flexibly andaccurately determine the projected signal.

In an example, the sixth communication device may be configured todetermine the estimated signal state information based on a receivedsample signal based on a sample signal that is transmitted from thefirst communication device and a sample signal that is transmitted fromthe fifth communication device. The received sample signals may includea pilot signal.

In an example, the first communication device and the fifthcommunication device may be configured to transmit sample signals basedon a time division multiplexing technology. The first communicationdevice and the fifth communication device may be configured to transmitpilot signals in time periods in which no pilot signal is transmittedfrom the third communication device. Thus, the sixth communicationdevice may be configured to efficiently determine the estimated signalstate information based on channel reciprocity. Further, the firstcommunication device and the fifth communication device may beconfigured to transmit null subcarriers based on subcarriers that aretransmitted by the third communication device and include pilot signals.Thus, the first communication device and the fifth communication devicemay be configured to increase the accuracy of determined channelparameters.

In an example, the sixth communication device may be configured totransmit sample signals based on a frequency division multiplexingtechnology. The sixth communication device may be configured to transmitpilot signals based on subcarriers based on which null subcarriers aretransmitted from the third communication device. Thus, the sixthcommunication device may be configured to efficiently determine theestimated signal state information. Further, the sixth communicationdevice may be configured to transmit null subcarriers based on whichpilot signals are transmitted by the third communication device. Thesixth communication device may be configured to transmit precodedsignals instead of null subcarriers. Thus, the sixth communicationdevice may be configured to increase the data rate.

In an example, aspects based on the circuit 406 of FIG. 4 may be aspectsof the circuit 606.

In an example, the communication device 602 of FIG. 6 may be based onthe communication devices based on FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG.5 and FIG. 6.

It should be noted that aspects of the communication device 602 of FIG.6 may be combined with aspects of the communication devices based onFIG. 1, FIG. 2, FIG. 3 and FIG. 4. Aspects of the communication device602 of FIG. 6 may be combined with aspects of the scenarios based onFIG. 1, FIG. 2 and FIG. 5.

FIG. 7 shows a schematic diagram of a communication device 702 that mayinclude a transmitter 704 and a circuit 706. The circuit 706 may beconnected with the transmitter 704. Features of FIG. 7 that may besimilar to features based on FIG. 5 and FIG. 6 may be referenced alike.

The circuit 706 may be configured to determine the estimated thirdsignal state information based on an interpolation of the received thirdsignal and a received sixth signal. Thus, the circuit 706 may beconfigured to accurately determine a data basis for the determination ofthe projected signals.

The circuit 706 may be configured to determine an interpolated thirdsignal based on the third signal and the sixth signal.

A shaped interpolated third signal may be shaped based on theinterpolated third signal in correspondence to the estimated secondlinear process.

The circuit 706 may be configured to determine a projected interpolatedthird signal based on the interpolated third signal and the secondprojection information.

A shaped projected interpolated third signal may be shaped based on theprojected interpolated third signal in correspondence to the estimatedsecond linear process.

A shaped interpolated fourth signal may be shaped based on theinterpolated second signal in correspondence to the estimated secondlinear process.

The circuit 706 may be configured to determine a projected interpolatedfourth signal based on the interpolated second signal and the secondprojection information.

A shaped projected interpolated fourth signal may be shaped based on theprojected interpolated fourth signal in correspondence to the estimatedsecond linear process.

The circuit 706 may be configured to determine an interpolated shapedinterpolated third signal based on the shaped interpolated third signaland the shaped interpolated fourth signal.

The circuit 706 may be configured to determine an interpolated shapedprojected interpolated third signal based on the shaped projectedinterpolated third signal and the shaped projected interpolated fourthsignal.

The circuit 706 may be configured to determine the second projectioninformation based on the estimated second linear process, theinterpolated second signal and the interpolated third signal such that aseventh absolute value of a seventh scalar product of a projectedinterpolated third signal and the interpolated shaped projectedinterpolated third signal is smaller than an eighth absolute value of aneighth scalar product of the interpolated third signal and theinterpolated shaped interpolated third signal. Thus, the circuit 706 maybe configured to effectively reduce the interference of uplink signalswith signals that the second communication device 108 receives fromother communication devices.

In an example, the circuit 706 may be a baseband circuit.

In an example, the circuit 706 may be configured to determine theestimated third signal state information based on weight factors thatare associated with the received third signal and the received sixthsignal based on distances of the first communication device 504 and thefifth communication device 510 to the second communication device 510.The weight of the weight factor decreases based on an increase of thedistance of the respective communication device to the secondcommunication device 510. Thus, the circuit 706 may be configured toincrease the accuracy of the data basis for the determination of theprojected signals.

In an example, the transmitter 704 may be configured to transmit signalsbased on at least one of time division multiplexing and frequencydivision multiplexing.

In an example, aspects based on the circuit 606 of FIG. 6 may be aspectsof the circuit 706.

In an example, the communication device 702 of FIG. 7 may be based onthe communication devices of FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5 andFIG. 6.

It should be noted that aspects of the communication device 702 of FIG.7 may be combined with aspects of the communication devices based onFIG. 3, FIG. 4 and FIG. 6. Aspects of the communication device 702 ofFIG. 7 may be combined with aspects of the scenarios based on FIG. 1,FIG. 2 and FIG. 5.

FIG. 8 shows a schematic diagram of a scenario in which a sixthcommunication device 812 may be configured to transmit signals in afirst cell 802 based on a shared frequency range. A second communicationdevice 808 may be configured to transmit signals in a second cell 804based on the shared frequency range. The second cell 804 may share ashared area 806 with the first cell 802.

A first communication device 810 and the second communication device 808may be configured to receive signals from the sixth communication device812 based on the shared frequency range. A third communication device818 may be configured to transmit signals to the second communicationdevice 808 based on the shared frequency range.

The sixth communication device 812 may be configured to transmit thesignals in a first sector 830, a second sector 832 and a third sector834.

It should be noted that aspects of the scenario of FIG. 8 may becombined with aspects of the communication devices based on FIG. 3, FIG.4, FIG. 6 and FIG. 7. Aspects of the scenario of FIG. 8 may be combinedwith aspects of the scenarios based on FIG. 1, FIG. 2 and FIG. 5.

FIG. 9 shows a schematic diagram of a communication device 902 that mayinclude a receiver 904 and a circuit 906. The receiver 904 may beconnected with the circuit 906. Features based on FIG. 8 that may besimilar to features of FIG. 9 may be referenced alike.

The circuit 906 may be configured to determine formed signal based on alocation information. The circuit 906 may be configured to determine theformed signal such that a received second energy based on the formedsignal that is received from the second communication device 808 issmaller than a received first energy based on the formed signal that isreceived from the first communication device 810. Thus, the circuit 906may be configured to effectively form signals based on a location of acommunication device such that the received energy of the communicationdevice is reduced.

In an example, the circuit 906 may be a baseband circuit.

In an example, the signals that are received from the firstcommunication device may comprise the location information. Thus, thecircuit 906 may be configured to obtain a reliable location information.

In an example, the formed signal may be based on the shared frequency.

In an example, the transmitter may be configured to transmit signals ina plurality of sectors in an angular distribution. The secondcommunication device may be in the second sector 832. The circuit 906may be configured to form the signal such that the transmitted power inthe second sector 832 is smaller than each of the transmitted powersthat are transmitted in different sectors based on the formed signal.Thus, the circuit 906 may be configured to efficiently reduce a receivedenergy of the second communication device.

In an example, the formed signal is not transmitted in the second sector832. Thus, the circuit 906 may be configured to reliably reduce areceived energy of the second communication device.

In an example, the communication device 902 of FIG. 9 may be based onthe communication devices based on FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG.5, FIG. 6, FIG. 7 and FIG. 8.

It should be noted that aspects of the communication device 902 of FIG.9 may be combined with aspects of the communication devices based onFIG. 3, FIG. 4, FIG. 6 and FIG. 7. Aspects of the communication device902 of FIG. 9 may be combined with aspects of the scenarios based onFIG. 1, FIG. 2, FIG. 5 and FIG. 8.

FIG. 10 shows a schematic diagram of a scenario in which a use of theshared frequency range is restricted in an Exclusion-, Protection- orRestriction (EPR) zone 804. Features FIG. 10 that may be similar tofeatures based on FIG. 8 may be referenced alike.

A base station 1012 may be configured to provide radio frequencyconnections based on the shared frequency range in a first cell 802. Thebase station 1012 may be configured to transmit signals in the firstsector 830 and the second sector 834. Further, the base station 1012 maybe configured to provide radio frequency connections based on a secondfrequency range that is different from the shared frequency range. Thebase station 1012 may be based on the communication device 902 of FIG.9.

The first communication device 810 may be configured to receive signalsbased on the second frequency range in the first sector 830. The secondcommunication device 808 may be configured to receive signals from thethird communication device 818 based on the shared frequency range. Afourth communication device 1014 may be configured to receive signalsbased on the shared frequency range in the third sector 834.

The base station 1012 may be configured to prevent radio frequencytransmissions based on the shared frequency range in the second sector832. Thus, an interference of signals that are received by the secondcommunication device 808 with signals of the third communication device818 may be reliably reduced.

In an example, aspects of the communication device 902 based on FIG. 9may be aspects of the base station 1012.

It should be noted that aspects of the scenario of FIG. 10 may becombined with aspects of the communication devices based on FIG. 3, FIG.4, FIG. 6, FIG. 7 and FIG. 9. Aspects of the scenario of FIG. 10 may becombined with aspects of the scenarios based on FIG. 1, FIG. 2, FIG. 5and FIG. 8.

FIG. 11 shows a schematic diagram of a scenario in which the basestation 1012 may be configured to provide a radio frequency connectionto the fourth communication device 1014. Features of FIG. 11 that may besimilar to features based on FIG. 10 may be referenced alike.

The fourth communication device 1014 may be in the first cell 802 andoutside of the EPR zone 804. The fourth communication device 1014 may beconfigured to connect with the base station 1012 based on the secondfrequency range.

In an example, aspects of the base station 1012 of FIG. 10 may beaspects of the base station 1012 of FIG. 11.

Aspects of FIG. 11 may be combined with aspects based on FIG. 8 and FIG.10.

It should be noted that aspects of the scenario of FIG. 11 may becombined with aspects of the communication devices based on FIG. 3, FIG.4, FIG. 6, FIG. 7 and FIG. 9. Aspects of the scenario of FIG. 11 may becombined with aspects of the scenarios based on FIG. 1, FIG. 2, FIG. 5,FIG. 8 and FIG. 10.

FIG. 12 shows a schematic diagram of a scenario in which the fourthcommunication device 1014 may be moved to the shared area 806 to thefirst sector 830. Features of FIG. 12 that may be similar to featuresbased on FIG. 11 may be referenced alike.

The fourth communication device 1014 may be configured to perform ahandover procedure from the second frequency range to the sharedfrequency range in case a change of frequencies is desired.

Aspects of FIG. 12 may correspond to aspects based on FIG. 8, FIG. 10and FIG. 11.

It should be noted that aspects of the scenario of FIG. 12 may becombined with aspects of the communication devices based on FIG. 3, FIG.4, FIG. 6, FIG. 7 and FIG. 9. Aspects of the scenario of FIG. 12 may becombined with aspects of the scenarios based on FIG. 1, FIG. 2, FIG. 5,FIG. 8, FIG. 10 and FIG. 11.

FIG. 13 shows a schematic diagram of a scenario in which the fourthcommunication device 1014 may be moved in the shared area 806 to thesecond sector 832.

The fourth communication device 1014 may be configured to perform ahandover procedure from the shared frequency range to the secondfrequency range.

Aspects of FIG. 13 may be combined with aspects based on FIG. 8, FIG.10, FIG. 11 and FIG. 12.

It should be noted that aspects of the scenario of FIG. 13 may becombined with aspects of the communication devices based on FIG. 3, FIG.4, FIG. 6, FIG. 7 and FIG. 9. Aspects of the scenario of FIG. 13 may becombined with aspects of the scenarios based on FIG. 1, FIG. 2, FIG. 5,FIG. 8, FIG. 10, FIG. 11 and FIG. 12.

FIG. 14 shows a schematic diagram of a scenario in which the fourthcommunication device 1014 may be moved in the shared area 806 to thethird sector 833.

The fourth communication device 1014 may be configured to perform ahandover procedure from the shared frequency range to the secondfrequency range in case a change of frequencies is desired.

If a connection based on the shared frequency range and the secondfrequency range is desired the fourth communication device 1014 may beconfigured to perform an initialization procedure for an additionalconnection to the base station 1012 based on the shared frequency range.

Aspects of FIG. 13 may correspond to aspects based on FIG. 8, FIG. 10,FIG. 11, FIG. 12 and FIG. 13.

It should be noted that aspects of the scenario of FIG. 14 may becombined with aspects of the communication devices based on FIG. 3, FIG.4, FIG. 6, FIG. 7 and FIG. 9. Aspects of the scenario of FIG. 14 may becombined with aspects of the scenarios based on FIG. 1, FIG. 2, FIG. 5,FIG. 8, FIG. 10, FIG. 11, FIG. 12 and FIG. 13.

FIG. 15 shows a schematic diagram of a communication device 1502 thatmay include a receiver 1504 and a circuit 1506. The receiver 1504 may beconnected with the circuit 1506. Features of FIG. 15 that may be similarto features based on FIG. 9 may be referenced alike.

The circuit 1506 may be configured to transmit a first signal and theformed signal. The circuit 1506 may be configured to estimate a signalstate information to determine an estimated signal state information.The signal state information may be based on a received first signalthat is received from the second communication device 808 based on thefirst signal.

The circuit 1506 may be configured to determine the shaped formed signalbased on the formed signal received from the second communication deviceand filtered by a filter of the second communication device.

The circuit 1506 may be configured to determine a shaped signal based onthe received first signal filtered by the filter of the secondcommunication device.

The circuit 1506 may be configured to determine the formed signal basedon the estimated signal state information and the second signal suchthat an energy of the shaped formed signal is smaller than an energy ofthe shaped signal. Thus, the circuit 1506 may be configured toeffectively reduce a received interference energy at a secondcommunication device based on signals from a third communication device.

In an example, the circuit 1506 may be a baseband circuit.

In an example, the circuit 1506 may be configured to determine theshaped formed signal based on the formed signal such that the formedsignal is shaped based on the estimated signal state information andfiltered by the filter of the second communication device.

In an example, the circuit 1506 may be configured to determine a shapedsignal based on a second signal such that the second signal is shapedbased on the estimated signal state information and filtered by thefilter of the second communication device.

In an example, aspects of the circuit 906 of FIG. 9 may be aspects ofthe circuit 1506.

In an example, the communication device 1502 of FIG. 15 may be based onthe communication devices based on FIG. 3, FIG. 4, FIG. 6, FIG. 7 andFIG. 9. In an example, aspects of the communication devices based onFIG. 3, FIG. 4, FIG. 6, FIG. 7 and FIG. 9 may be aspects of thecommunication device 1502 of FIG. 15.

It should be noted that aspects of the communication device 1502 of FIG.15 may be combined with aspects of the communication devices based onFIG. 3, FIG. 4, FIG. 6, FIG. 7 and FIG. 9. Aspects of the communicationdevice 1502 of FIG. 15 may be combined with aspects of the scenariosbased on FIG. 1, FIG. 2, FIG. 5, FIG. 8, FIG. 10, FIG. 11, FIG. 12, FIG.13 and FIG. 14.

FIG. 16 shows a schematic diagram of a scenario in which a first basestation 1618 may be configured to provide radio frequency connectionsbased on a first frequency. A first communication device 1610 may beconfigured to receive signals based on the first frequency. A secondbase station 1620 may be configured to provide radio frequencyconnections based on a shared frequency and based on a second frequencyin a first cell 1602. A fourth communication device 1616 may beconfigured to connect via radio frequency connections based on the firstfrequency and the shared frequency. A second communication device 1612may be configured to provide radio frequency connections based on theshared frequency in a second cell 1604. The second cell 1604 may cover ashared area 1606 that may be covered from the first cell 1602. A thirdcommunication device 1614 may be configured to connect via radiofrequency connections to the second communication device 1612 based onthe shared frequency. The second base station 1620 may be configured totransmit signals in a first sector 1630 and a third sector 1634.Further, the second base station 1620 may be configured to prevent totransmit signals in a second sector 1632.

In an example, the fourth communication device 1616 may be connectedwith the second base station 1620 based on the second frequency. Thefourth communication device 1620 may be configured to select the secondbase station 1620 based on the shared frequency. Thus, the fourthcommunication device 1620 may be configured to flexibly select aconnection that provides a higher data rate.

In an example, the fourth communication device 1616 may be connectedwith the second base station 1620 based on the second frequency. Thefourth communication device 1620 may be configured to select the secondbase station 1620 based on the shared frequency in addition to theconnection based on the second frequency. Thus, the fourth communicationdevice 1616 may be configured to exploit the available spectrum toincrease data rates, provide a stable connection and flexibly utilizeone connection as downlink and the other connection as uplink.

In an example, the fourth communication device 1616 may be connectedwith the first base station 1618 based on the first frequency. Thefourth communication device 1620 may be configured to select the secondbase station 1620 based on the shared frequency. Thus, the fourthcommunication device 1620 may be configured to flexibly select aconnection that provides a higher data rate.

In an example, the fourth communication device 1616 may be connectedwith the first base station 1618 based on the first frequency. Thefourth communication device 1620 may be configured to select the secondbase station 1620 based on the shared frequency in addition to theconnection to the first base station 1618 based on the first frequency.Thus, the fourth communication device 1616 may be configured to exploitthe available spectrum to increase data rates, provide a reliableconnection and flexibly utilize one connection as downlink and the otherconnection as uplink.

In an example, the fourth communication device 1616 may be connected tothe first base station 1618 based on the first frequency. The fourthcommunication device 1616 may be configured to receive a signal from thefirst base station 1618 that may include a reselection preventioninformation. The reselection prevention information may indicate thatthe fourth communication device 1616 is prohibited to select a basestation based on the first frequency.

It should be noted that aspects of the scenario of FIG. 16 may becombined with aspects of the communication devices based on FIG. 3, FIG.4, FIG. 6, FIG. 7, FIG. 9 and FIG. 15. Aspects of the scenario of FIG.16 may be combined with aspects of the scenarios based on FIG. 1, FIG.2, FIG. 5, FIG. 8, FIG. 10, FIG. 11, FIG. 12, FIG. 13 and FIG. 14.

FIG. 17 shows a schematic diagram of a first communication device 1702that may include a receiver 1704, a determination circuit 1705 and acircuit 1706. The receiver 1704 may be connected with the determinationcircuit 1705. The determination circuit 1705 may be connected with thecircuit 1706.

The receiver 1704 may be configured to receive a first signal from thesecond base station and a second signal from the third communicationdevice. The first signal and the second signal may be based on a sharedfrequency.

The determination circuit 1705 may be configured to determine a firstpower level of the first signal and a second power level of the secondsignal.

The circuit 1706 may be configured to determine a power ratio of thefirst power level to the second power level. The circuit 1706 may beconfigured to determine a third signal that comprises an interferenceparameter information based on the power ratio. Thus, the firstcommunication device 1702 may be configured to measure an interferencelevel of signals from a base station with signals from a thirdcommunication device. Further, the first communication device 1702 maybe configured to efficiently inform about an interference level of abase station and a communication device.

In an example, the circuit 1706 may be a baseband circuit.

In an example, the circuit 1706 may be configured to determine theinterference parameter to indicate if the power ratio is smaller than athreshold.

In an example, the second communication device 1612 may be configured toprovide the threshold to the first communication device 1702.

In an example, the second communication device 1612 may be configured toprovide the threshold to the first communication device 1702. Thethreshold may indicate a required minimum signal to interference ratio.The signal to interference ratio may be a ratio of a first power levelof a received first signal received by the second communication device1612 to a received interference signal received by the secondcommunication device.

In an example, the second communication device 1612 may be configured todetermine a filter characteristic vector provided to filter the receivedsignal. The filter characteristic vector may be based on a vector ofreceived signals received by a multiple input multiple output receiver.Further, the second communication device 1612 may be configured totransmit the information representative of the determined filtercharacteristic vector to the other communication device.

In an example, the first communication device 1702 may be configured toperiodically determine the signal to interference ratios and report thedetermined signal to interference ratios to the second base stationand/or the fourth communication device 1902. Thus, the firstcommunication device may be effectively configured to reliably reduce aninterference at the incumbent base station with signals that arereceived at the incumbent base station in the first radio frequencyrange.

In an example, the first communication device 1702 may be configured toreceive the threshold from the second communication device. Thus, thecommunication system may be configured to reliably reduce aninterference of interference signals based on the shared frequency withsignals of a third communication device at a second communicationdevice.

In an example, the first communication device 1702 of FIG. 17 may bebased on the communication devices based on FIG. 3, FIG. 4, FIG. 6, FIG.7, FIG. 9 and FIG. 15.

It should be noted that aspects of the first communication device 1702of FIG. 17 may be combined with aspects of the communication devicesbased on FIG. 3, FIG. 4, FIG. 6, FIG. 7, FIG. 9 and FIG. 15. Aspects ofthe first communication device 1702 of FIG. 17 may be combined withaspects of the scenarios based on FIG. 1, FIG. 2, FIG. 5, FIG. 8, FIG.10, FIG. 11, FIG. 12, FIG. 13, FIG. 14 and FIG. 16.

FIG. 18 shows a schematic diagram of the second base station 1802 thatmay include a transmitter 1803, a receiver 1804 and a circuit 1806. Thereceiver 1804 may be connected with the circuit 1806.

The transmitter 1803 may be configured to transmit signals based on ashared frequency.

The receiver 1804 may be configured to receive a connection requestsignal based on the shared frequency from a fourth communication device.

The circuit 1806 may be configured to determine a first signal based onthe shared frequency that comprises a request information of aninterference parameter. The circuit 1806 may be configured to determinesignals based on the interference parameter to transmit based on theshared frequency. Thus, the second base station 1802 may be configuredto efficiently determine if an interference level of downlink signals islow enough to provide a connection based on the downlink signals. Therequest information of the interference parameter may include a requestto receive the interference parameter.

In an example, the circuit 1806 may be a baseband circuit.

In an example, if the measured signal to interference ratio in a searchprocess of a fourth communication device 1902 in all frequency bands ofthe second base station 1802 is greater than the threshold the secondbase station 1802 may be configured to transmit a message to the fourthcommunication device 1902 that indicates that the fourth communicationdevice 1902 may be prohibited from selecting the second base station1802. The second base station 1802 may be barred. Thus, the second basestation 1802 may be configured to effectively prevent high interferencelevels with signals of a third communication device at the secondcommunication device.

In an example, the second base station 1802 of FIG. 18 may be based onthe communication devices based on FIG. 3, FIG. 4, FIG. 6, FIG. 7, FIG.9, FIG. 15 and FIG. 17.

It should be noted that aspects of the second base station 1802 of FIG.18 may be combined with aspects of the communication devices based onFIG. 3, FIG. 4, FIG. 6, FIG. 7, FIG. 9, FIG. 15 and FIG. 17. Aspects ofthe second base station 1802 of FIG. 18 may be combined with aspects ofthe scenarios based on FIG. 1, FIG. 2, FIG. 5, FIG. 8, FIG. 10, FIG. 11,FIG. 12, FIG. 13, FIG. 14 and FIG. 16.

FIG. 19 shows a schematic diagram of a fourth communication device 1902that may include a receiver 1904 and a circuit 1906. The receiver 1904may be connected with the circuit 1906.

The receiver 1904 may be configured to receive signals from basestations.

The circuit 1906 may be configured to select a second base station fromthe base stations. The first base station may be configured to transmita first signal. A first communication device may be configured toreceive a received first signal. A third communication device may beconfigured to transmit a second signal. The first communication devicemay be configured to receive a received second signal. A parameter maybe based on a first power level of the first signal and a second powerlevel of the second signal. The circuit 1906 may be configured to selectthe first base station based on the parameter. Thus, the fourthcommunication device 1902 may be configured to effectively connect to abase station based on a restricted frequency.

In an example, the circuit 1906 may be a baseband circuit.

In an example, the circuit 1906 may be configured to determine a signalselection receive level S_(rxlev) of a third signal that is receivedfrom the second base station based on measured signal receive levelQ_(rxlevmeas) of the third signal, a minimum required receive levelQ_(rxlevmin), a first offset Q_(rxlevminoffset), a maximum uplinktransmission power level P_(EMAX), a maximum radio frequency outputpower P_(PowerClass), a compensation power level P_(compensation) and atemporarily applied offset Q_(offsettemp) by a formula (30):

S _(rxlev) =Q _(rxlevmeas)−(Q _(rxlevmin) +Q _(rxlevminoffset))−max(P_(EMAX) −P _(PowerClass),0)−Q _(offsettemp).   (30)

Further, the circuit 1906 may be configured to determine a signalselection quality value S_(qual) of the third signal based on a measuredsignal quality value of the third signal Q_(qualmeas), a minimumrequired quality level of the signal Q_(qualmin), an offsetQ_(qualminoffset) that may be an offset to the signaled Q_(qualmin) anda temporarily applied offset Q_(offsettemp) by a formula (31):

S _(qual) =Q _(qualmeas)−(Q _(qualmin) +Q _(qualminoffset))−Q_(offsettemp).  (31)

The circuit 1906 may be configured to select the second base stationonly if the signal selection receive level S_(rxlev) of the third signalis greater than zero and the signal selection quality value S_(qual) ofthe third signal is greater than zero. Thus, the communication device1902 may be configured to ensure a minimally required signal quality ofa radio frequency signal.

In an example, the fourth communication device 1902 may be configured toexclude a barred base station and base stations based on the samefrequency as the frequency with respect to which the barred base stationis barred as candidate for selection in a time period of 300 seconds.Thus, the fourth communication device 1902 may be configured to avoidunnecessary traffic.

In an example, the fourth communication device 1902 of FIG. 19 may bebased on the communication devices based on FIG. 3, FIG. 4, FIG. 6, FIG.7, FIG. 9, FIG. 15, FIG. 17 and FIG. 18.

It should be noted that aspects of the fourth communication device 1902of FIG. 19 may be combined with aspects of the communication devicesbased on FIG. 3, FIG. 4, FIG. 6, FIG. 7, FIG. 9, FIG. 15, FIG. 17 andFIG. 18. Aspects of the fourth communication device 1902 of FIG. 19 maybe combined with aspects of the scenarios based on FIG. 1, FIG. 2, FIG.5, FIG. 8, FIG. 10, FIG. 11, FIG. 12, FIG. 13, FIG. 14 and FIG. 16.

FIG. 20 shows a schematic diagram of a selection scenario which may bebased on the first communication device 1702 of FIG. 17, the second basestation 1802 of FIG. 18 and the fourth communication device 1902 of FIG.19. The diagram shows an execution flow of execution steps that thefourth communication device 1902, the second base station 1802, a firstbase station 2030 and the first communication device 1702 may beconfigured to execute in a time order that may be indicated by a timeaxis 2000.

A second communication device may be configured to transmit and receivesignals based on a shared frequency band in a first cell. The secondbase station 1802 may be configured to transmit signals based on theshared frequency band in a second cell. The second cell may cover ashared area that may be covered by the first cell. The fourthcommunication device 1902 and the first communication device 1702 may belocated in the shared area. Further, a third communication device may beconfigured to transmit signals based on the shared frequency band.

In 2002, the fourth communication device 1902 may be configured to scanall radio frequency channels based on a shared frequency band. In anexample, the scan may be restricted to frequency bands based on aUniversal Mobile Telecommunications System (UMTS) of an evolved UMTSTerrestrial Radio Access (e-UTRA) system. Further, the fourthcommunication device 1902 may be configured to base stations based on ashared frequency band that have a selection receive level S_(rxlev) thatis greater than zero and a selection quality value S_(qual) that isgreater than zero. Further, the fourth communication device 1902 may beconfigured to select a base station from the detected base stations thathas the greatest signal power from the detected base stations. Moreover,the fourth communication device 1902 may be configured to send afeedback signal that includes an information about the selected basestation to the second base station 1802.

In 2004, the second base station 1802 may be configured to request aninformation that indicates a communication device such that the distanceof the communication device to the second communication device is asmallest distance from distances of communication devices that areavailable in the second cell.

In 2006, the first base station 2030 may be configured to determine acommunication device that may be located closest to the secondcommunication device and to send the requested information to the secondbase station 1802.

In 2008, the second base station 1802 may be configured to transmit afirst reference signal based on the shared frequency band.

In 2010, the first communication device 1702 may be configured todetermine a first interference power level of a received first signalbased on the first reference signal and a second power level of areceived second signal that is transmitted by the third communicationdevice and received from the first communication device 1702. Moreover,the first communication device 1702 may be configured to determine afirst signal to interference ratio of the first interference power levelto the second power level. The first communication device 1702 may beconfigured to determine a first interference parameter to indicate ifthe first signal to interference ratio is smaller than a threshold.Further, the first communication device 1702 may be configured totransmit the first interference parameter to the first base station2030. In an example, the first communication device 1702 may beconfigured to transmit the first interference parameter to the secondbase station 1802.

In 2012, the first base station 2030 may be configured to transmit thefirst interference parameter to the second base station 1802.

In 2014, if the first signal to interference ratio is smaller than athreshold the second base station 1802 may be configured to establish adownlink connection with the fourth communication device 1902. Further,the second base station 1802 may be configured to request thetransmission of a second reference signal based on the shared frequencyband from the fourth communication device 1902. If the first signal tointerference ratio is greater than the threshold the second base station1802 may be configured to refuse a downlink connection with the fourthcommunication device 1902.

In 2016, the fourth communication device 1902 may be configured totransmit a second reference signal based on the shared frequency band.

In 2018, the first communication device 1702 may be configured todetermine a third interference power level of a received third signalbased on the second reference signal. Moreover, the first communicationdevice 1702 may be configured to determine a second signal tointerference ratio of the third interference power level to the secondpower level. The first communication device 1702 may be configured todetermine a second interference parameter to indicate if the secondsignal to interference ratio is smaller than a threshold. Further, thefirst communication device 1702 may be configured to transmit the secondinterference parameter to the first base station 2030. In an example,the first communication device 1702 may be configured to transmit thesecond interference parameter to the second base station 1802. In anexample, the first communication device 1702 may be configured totransmit the second interference parameter to the fourth communicationdevice 1902.

In 2020, the first base station 2030 may be configured to transmit thesecond interference parameter to the second base station 1802.

In 2022, if the second signal to interference ratio is smaller than thethreshold the second base station 1802 may be configured to permit anuplink connection with the fourth communication device 1902. If thesecond signal to interference ratio is greater than the threshold thesecond base station 1802 may be configured to refuse an uplinkconnection with the fourth communication device 1902. In an example, thesecond base station 1802 may be configured to transmit the secondinterference parameter to the fourth communication device 1902.

In an example, the fourth communication device 1902 may be connected tothe first base station 2030. The fourth communication device 1902 may beconfigured to reselect the second base station 1802 based on the sharedfrequency band. Thus, the fourth communication device may be configuredto efficiently reselect a second base station.

In an example, in the cell reselection process, if at least one of thecell selection receive level S_(rxlev) is smaller than zero, the cellselection quality value S_(qual) is smaller than zero, the first signalto interference ratio is greater than the threshold and the secondsignal to interference ratio is greater than the threshold the fourthcommunication device 1902 may be configured to perform inter frequencymeasurements and/or intra frequency measurements. Thus, the fourthcommunication device may be configured to reliably reselect a basestation.

In an example, the first base station 1702 may be configured to, onrequest of the second base station 1802, determine distances ofcommunication devices in recurring time intervals and report thecommunication device that corresponds to the smallest distance to thesecond base station 1802. The second base station 1802 may be configuredto forward the information of the reported communication device to thefourth communication device 1902. Thus, the second base station 1802 maybe configured to persistently reduce an interference of signals based onthe shared frequency range with signals of a third communication deviceat a second communication device.

The first communication device 1702, the fourth communication device1902, the first base station 2030 and the second base station 1802 ofFIG. 20 may be based on the communication devices based on FIG. 3, FIG.4, FIG. 6, FIG. 7, FIG. 9, FIG. 15, FIG. 17, FIG. 18 and FIG. 19.

It should be noted that aspects of the cell selection process of FIG. 20may be combined with aspects of the communication devices based on FIG.3, FIG. 4, FIG. 6, FIG. 7, FIG. 9, FIG. 15, FIG. 17, FIG. 18 and FIG.19. Aspects of the cell selection process of FIG. 20 may be combinedwith aspects of the scenarios based on FIG. 1, FIG. 2, FIG. 5, FIG. 8,FIG. 10, FIG. 11, FIG. 12, FIG. 13, FIG. 14 and FIG. 16.

FIG. 21 shows a schematic diagram of a communication system 2102 thatmay include a first communication device 2104 and a base station 2106.The first communication device 2104 may be connected to the base station2106 based on a radio frequency connection 2108.

The base station 2106 may be configured to transmit a sample signal.

In an example, the sample signal that is transmitted by the base station2106 is the first sample signal t₁.

The first communication device 2104 may be configured to determine anestimated signal state information. The estimated signal stateinformation may be an estimate of a signal state information. The signalstate information may be based on a third signal a₃ that is transmittedfrom the base station and a received third signal that is received fromthe second communication device. The estimated signal state informationmay be based on a third operator G₃.

In an example, the received signal that is received from the secondcommunication device may be the first interference signal w₁.

The base station 2106 may be configured to determine a projected thirdsignal p₃ based on the estimated signal state information such that anenergy of a shaped projected third signal u₃ is smaller than an energyof a shaped third signal s₃. The base station 2106 may be configured todetermine the shaped third signal s₃ based on the third signal a₃, theestimated signal state information and a filter of a secondcommunication device. The shaped third signal s₃ may be related with thethird signal a₃ based on the third operator G₃ by a formula (32):

S ₃ =G ₃ a ₃.  (32)

The base station 2106 may be configured to determine the shapedprojected third signal u₃ based on the projected third signal p₃, theestimated signal state information and the filter of the secondcommunication device. The shaped projected third signal u₃ may berelated with the projected third signal p₃ based on the third operatorG₃ by a formula (33):

u ₃ =G ₃ p ₃.  (33)

Further, the base station 2106 may be configured to transmit theprojected third signal p₃.Thus, the communication system 2102 may be configured to effectivelyreduce interference energies of interference signals that interfere withsignals that are transmitted from a third communication device andreceived from the second communication device.

In an example, the second communication device may be configured toreceive the energy of the shaped projected third signal u₃ and theenergy of the shaped third signal s₃ in a predefined time period.

In an example, the energy of the shaped projected third signal u₃ may bean estimated energy of the shaped projected third signal u₃. The energyof the shaped third signal s₃ may be an estimated energy of the shapedthird signal s₃.

In an example, the base station 2106 may be configured to estimate theestimated energy of the shaped projected third signal u₃ and theestimated energy of the shaped third signal s₃ based on the estimatedsignal state information and the filter of the second communicationdevice.

In an example, the communication device 2104 of FIG. 21 may be based onthe communication devices based on FIG. 3, FIG. 4, FIG. 6, FIG. 7, FIG.9, FIG. 15, FIG. 17, FIG. 18 and FIG. 19.

In an example, the base station 2106 of FIG. 21 may be based on thecommunication devices based on FIG. 3, FIG. 4, FIG. 6, FIG. 7, FIG. 9,FIG. 15, FIG. 17, FIG. 18 and FIG. 19.

It should be noted that aspects of the communication system 2102 of FIG.21 may be combined with aspects of the communication devices based onFIG. 3, FIG. 4, FIG. 6, FIG. 7, FIG. 9, FIG. 15, FIG. 17, FIG. 18 andFIG. 19. Aspects of the communication system 2102 of FIG. 21 may becombined with aspects of the scenarios based on FIG. 1, FIG. 2, FIG. 5,FIG. 8, FIG. 10, FIG. 11, FIG. 12, FIG. 13, FIG. 14, FIG. 16 and FIG.20.

FIG. 22 shows a method for radio communication according to an example.

The method may include, in 2202, transmitting a first signal and aprojected signal.

The method may include, in 2204, determining the projected signal basedon an estimated signal state information such that an energy of a shapedprojected signal is smaller than an energy of a shaped signal. Theestimated signal state information may be an estimate of a signal stateinformation based on the first signal and a received signal that isreceived by a receiver of a second communication device. The shapedprojected signal may be the projected signal received by the receiver ofthe second communication device and filtered by a filter of the secondcommunication device. The shaped signal may be the received signalfiltered by the filter of the second communication device.

In an example, the method of FIG. 22 may be performed by a communicationdevice based on FIG. 3, FIG. 4, FIG. 6 and FIG. 7.

FIG. 23 shows a method for radio communication according to an example.

The method may include, in 2302, receiving signals from a firstcommunication device.

The method may include, in 2304, determining a formed signal based on alocation information of a second communication device such that areceived second energy based on the formed signal that is received fromthe second communication device is smaller than a received first energybased on the formed signal that is received from the first communicationdevice.

In an example, the method of FIG. 23 may be performed by a communicationdevice based on FIG. 9 and FIG. 15.

FIG. 24 shows a method for radio communication according to an example.

The method may include, in 2402, receiving a first signal from a basestation and a second signal from a first communication device.

The method may include, in 2404, determining a first power level of thefirst signal and a second power level of the second signal.

The method may include, in 2406, determining a power ratio of the firstpower level to the second power level.

The method may include, in 2408, determining a third signal thatcomprises an interference parameter information based on the powerratio, wherein the first signal and the second signal are based on ashared frequency.

In an example, the method of FIG. 24 may be performed by a communicationdevice based on FIG. 17.

FIG. 25 shows a method for radio communication according to an example.

The method may include, in 2502, transmitting signals based on a sharedfrequency.

The method may include, in 2504, receiving a connection request signalbased on the shared frequency from a first communication device.

The method may include, in 2506, determining a first signal based on theshared frequency that comprises a request information of an interferenceparameter.

The method may include, in 2508, determining signals based on theinterference parameter to transmit based on the shared frequency.

In an example, the method of FIG. 25 may be performed by a communicationdevice based on FIG. 18.

FIG. 26 shows a method for radio communication according to an example.

The method may include, in 2602, receiving signals from base stations.

The method may include, in 2604, selecting a first base station from thebase stations. Further, a first signal may be transmitted from the firstbase station and a received first signal is received from a secondcommunication device. Moreover, a second signal may be transmitted froma third communication device and a received second signal is receivedfrom the second communication device. Further, a parameter may be basedon a first power level of the received first signal and a second powerlevel of the received second signal. The first base station may beselected based on the parameter.

In an example, the method of FIG. 26 may be performed by a communicationdevice based on FIG. 19.

FIG. 27 shows a method for radio communication according to an example.

The method may include, in 2702, determining an estimated signal stateinformation.

The method may include, in 2704, transmitting a first signal and aprojected signal.

The method may include, in 2706, determining the projected signal basedon an estimated signal state information such that an energy of a shapedprojected signal is smaller than an energy of a shaped signal. Theestimated signal state information may be an estimate of a signal stateinformation based on the first signal and a received signal that isreceived by a receiver of a second communication device. The shapedprojected signal may be the projected signal received by the receiver ofthe second communication device and filtered by a filter of the secondcommunication device. The shaped signal may be the received signalfiltered by the filter of the second communication device.

In an example, the method of FIG. 27 may be performed by a communicationsystem based on FIG. 21.

FIG. 28 shows a method of operating a communication device according toan example.

The method may include, in 2802, receiving a received signal transmittedby another communication device.

The method may include, in 2804, filtering the received signal tothereby generate a shaped signal.

The method may include, in 2806, determining a filter characteristicvector provided to filter the received signal.

The method may include, in 2808, transmitting the informationrepresentative of the determined filter characteristic vector to theother communication device.

It should be noted that aspects of the examples of FIG. 1, FIG. 2, FIG.3, FIG. 4, FIG. 5, FIG. 6, FIG. 7, FIG. 8, FIG. 9, FIG. 10, FIG. 11,FIG. 12, FIG. 13, FIG. 14, FIG. 15, FIG. 16, FIG. 17, FIG. 18, FIG. 19,FIG. 20, FIG. 21 and FIG. 22 may be combined with aspects of the abovedescribed methods.

FIG. 29 may be a schematic diagram that shows a communication device2902. The communication device 2902 may include a receiver 2904configured to receive a received signal transmitted by anothercommunication device. Further, the communication device 2902 may includea filter 2906 configured to filter the received signal to therebygenerate a shaped signal. Further, the communication device 2902 mayinclude a circuit 2908 configured to determine a filter characteristicvector provided to filter the received signal. Further, thecommunication device 2902 may include a transmitter 2910 configured totransmit the information representative of the determined filtercharacteristic vector to the other communication device. Thus, thecommunication device may be configured to efficiently reduce aninterference of signals received from other communication devices.

It should be noted that aspects of the communication device of FIG. 29may be combined with aspects of the communication devices based on FIG.3, FIG. 4, FIG. 6, FIG. 7, FIG. 9, FIG. 15, FIG. 17, FIG. 18 and FIG.19. Aspects of the communication device of FIG. 29 may be combined withaspects of the scenarios based on FIG. 1, FIG. 2, FIG. 5, FIG. 8, FIG.10, FIG. 11, FIG. 12, FIG. 13, FIG. 14 and FIG. 16 and the cellselection process based on FIG. 22.

The radio frequency connections and signals of the examples based onFIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, FIG. 6, FIG. 7, FIG. 8, FIG. 9,FIG. 10, FIG. 11, FIG. 12, FIG. 13, FIG. 14, FIG. 15, FIG. 16, FIG. 17,FIG. 18, FIG. 19, FIG. 20, FIG. 21, FIG. 22, FIG. 23, FIG. 24, FIG. 25,FIG. 26 and FIG. 27 may be configured in accordance with any one or moreof the following radio communication technologies and/or standardsincluding but not limited to: a Global System for Mobile Communications(GSM) radio communication technology, a General Packet Radio Service(GPRS) radio communication technology, an Enhanced Data Rates for GSMEvolution (EDGE) radio communication technology, and/or a ThirdGeneration Partnership Project (3GPP) radio communication technology,for example Universal Mobile Telecommunications System (UMTS), Freedomof Multimedia Access (FOMA), 3GPP Long Term Evolution (LTE), 3GPP LongTerm Evolution Advanced (LTE Advanced), Code division multiple access2000 (CDMA2000), Cellular Digital Packet Data (CDPD), Mobitex, ThirdGeneration (3G), Circuit Switched Data (CSD), High-SpeedCircuit-Switched Data (HSCSD), Universal Mobile TelecommunicationsSystem (Third Generation) (UMTS (3G)), Wideband Code Division MultipleAccess (Universal Mobile Telecommunications System) (W-CDMA (UMTS)),High Speed Packet Access (HSPA), High-Speed Downlink Packet Access(HSDPA), High-Speed Uplink Packet Access (HSUPA), High Speed PacketAccess Plus (HSPA+), Universal Mobile TelecommunicationsSystem-Time-Division Duplex (UMTS-TDD), Time Division-Code DivisionMultiple Access (TD-CDMA), Time Division-Synchronous Code DivisionMultiple Access (TD-CDMA), 3rd Generation Partnership Project Release 8(Pre-4th Generation) (3GPP Rel. 8 (Pre-4G)), 3GPP Rel. 9 (3rd GenerationPartnership Project Release 9), 3GPP Rel. 10 (3rd Generation PartnershipProject Release 10), 3GPP Rel. 11 (3rd Generation Partnership ProjectRelease 11), 3GPP Rel. 12 (3rd Generation Partnership Project Release12), 3GPP Rel. 13 (3rd Generation Partnership Project Release 13), 3GPPRel. 14 (3rd Generation Partnership Project Release 14), 3GPP Rel. 15(3rd Generation Partnership Project Release 15), 3GPP Rel. 16 (3rdGeneration Partnership Project Release 16), 3GPP Rel. 17 (3rd GenerationPartnership Project Release 17), 3GPP Rel. 18 (3rd GenerationPartnership Project Release 18), 3GPP 5G, 3GPP LTE Extra, LTE-AdvancedPro, LTE Licensed-Assisted Access (LAA), MuLTEfire, UMTS TerrestrialRadio Access (UTRA), Evolved UMTS Terrestrial Radio Access (E-UTRA),Long Term Evolution Advanced (4th Generation) (LTE Advanced (4G)),cdmaOne (2G), Code division multiple access 2000 (Third generation)(CDMA2000 (3G)), Evolution-Data Optimized or Evolution-Data Only(EV-DO), Advanced Mobile Phone System (1st Generation) (AMPS (1G)),Total Access Communication System/Extended Total Access CommunicationSystem (TACS/ETACS), Digital AMPS (2nd Generation) (D-AMPS (2G)),Push-to-talk (PTT), Mobile Telephone System (MTS), Improved MobileTelephone System (IMTS), Advanced Mobile Telephone System (AMTS), OLT(Norwegian for Offentlig Landmobil Telefoni, Public Land MobileTelephony), MTD (Swedish abbreviation for Mobiltelefonisystem D, orMobile telephony system D), Public Automated Land Mobile (Autotel/PALM),ARP (Finnish for Autoradiopuhelin, “car radio phone”), NMT (NordicMobile Telephony), High capacity version of NTT (Nippon Telegraph andTelephone) (Hicap), Cellular Digital Packet Data (CDPD), Mobitex,DataTAC, Integrated Digital Enhanced Network (iDEN), Personal DigitalCellular (PDC), Circuit Switched Data (CSD), Personal Handy-phone System(PHS), Wideband Integrated Digital Enhanced Network (WiDEN), iBurst,Unlicensed Mobile Access (UMA), also referred to as also referred to as3GPP Generic Access Network, or GAN standard), Zigbee, Bluetooth,Wireless Gigabit Alliance (WiGig) standard, mmWave standards in general(wireless systems operating at 10-300 GHz and above such as WiGig, IEEE802.11ad, IEEE 802.11ay, etc.), technologies operating above 300 GHz andTHz bands, (3GPP/LTE based or IEEE 802.11p and other) Vehicle-to-Vehicle(V2V) and Vehicle-to-X (V2X) and Vehicle-to-Infrastructure (V2I) andInfrastructure-to-Vehicle (I2V) communication technologies, 3GPPcellular V2X, DSRC (Dedicated Short Range Communications) communicationsystems such as Intelligent-Transport-Systems and others.

The examples based on FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, FIG. 6,FIG. 7, FIG. 8, FIG. 9, FIG. 10, FIG. 11, FIG. 12, FIG. 13, FIG. 14,FIG. 15, FIG. 16, FIG. 17, FIG. 18, FIG. 19, FIG. 20, FIG. 21, FIG. 22,FIG. 23, FIG. 24, FIG. 25, FIG. 26 and FIG. 27 may be applicable basedon any spectrum management scheme including dedicated licensed spectrum,unlicensed spectrum, (licensed) shared spectrum such as Licensed SharedAccess (LSA) in 2.3-2.4 GHz, 3.4-3.6 GHz, 3.6-3.8 GHz and furtherfrequencies and Spectrum Access System (SAS) in 3.55-3.7 GHz and furtherfrequencies. Applicable spectrum bands include International MobileTelecommunications (IMT) spectrum, IMT-advanced spectrum, IMT-2020spectrum and spectrum made available under FCC's “Spectrum Frontier” 5Ginitiative.

Further, the radio frequency connections and signals of the examples ofFIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG. 5, FIG. 6, FIG. 7, FIG. 8, FIG. 9,FIG. 10, FIG. 11, FIG. 12, FIG. 13, FIG. 14, FIG. 15, FIG. 16, FIG. 17,FIG. 18, FIG. 19, FIG. 20, FIG. 21, FIG. 22, FIG. 23, FIG. 24, FIG. 25,FIG. 26 and FIG. 27 may be based on Orthogonal Frequency DivisionMultiplexing (OFDM), for example Single Carrier-Frequency DivisionMultiple Access (SC-FDMA), Single Carrier-Orthogonal Frequency DivisionMultiplexing (SC-OFDM), Filter Bank-based Multicarrier (FBMC),Orthogonal Frequency Division Multiple Access (OFDMA) and 3GPP NR (NewRadio) by allocating the OFDM carrier data bit vectors to thecorresponding symbol resources.

In the following, various aspects of this disclosure will beillustrated:

Example 1 is a communication device. The communication device mayinclude a transmitter configured to transmit a first signal and aprojected signal. The communication device may include a circuitconfigured to determine the projected signal based on an estimatedsignal state information such that an energy of a shaped projectedsignal is smaller than an energy of a shaped signal. The estimatedsignal state information may be an estimate of a signal stateinformation based on the first signal and a received signal that may bereceived by a receiver of a second communication device. The shapedprojected signal may be the projected signal received by the receiver ofthe second communication device and filtered by a filter of the secondcommunication device. The shaped signal may be the received signalfiltered by the filter of the second communication device.

In Example 2, the subject matter of Example 1 can optionally includethat the projected signal may be determined in accordance with aMultiple Input Multiple Output communication technology.

In Example 3, the subject matter of any one of Examples 1 to 2 canoptionally include that the projected signal may be based on a firstvector of input signals. The first vector may be based on a firstplurality of input signals. The first signal may be based on a secondvector of input signals. The second vector may be based on a secondplurality of input signals.

In Example 4, the subject matter of Example 3 can optionally includethat the shaped projected signal may be based on a third vector ofoutput signals. The third vector may be based on a third plurality ofoutput signals that may be received by the receiver of the secondcommunication device based on the projected signal. The shaped signalmay be based on a fourth vector of output signals. The fourth vector maybe based on a fourth plurality of output signals that may be received bythe receiver of the second communication device based on the firstsignal.

In Example 5, the subject matter of Example 4 can optionally includethat the transmitter may be configured to transmit signals based on aplurality of antennas. The signals of the first vector may betransmitted based on the antennas of the plurality of antennas,respectively. The signals of the second vector may be transmitted basedon the antennas of the plurality of antennas, respectively.

In Example 6, the subject matter of any one of Examples 4 to 5 canoptionally include that the circuit may be configured to determine thefirst vector such that a first absolute value of a first scalar productof the first vector and the third vector is smaller than a secondabsolute value of a second scalar product of the second vector and thefourth vector.

In Example 7, the subject matter of any one of Examples 1 to 6 canoptionally include that a second signal state information may be basedon a third signal that may be transmitted from a third communicationdevice and a received third signal that may be received by the receiverof the second communication device. The second signal state informationmay be an estimate of a channel state information. The filter may beconfigured to filter based on the channel state information.

In Example 8, the subject matter of Example 7 can optionally includethat the circuit may be configured to determine the projected signalbased on an estimated linear process. The circuit may be configured todetermine the estimated linear process based on the estimated signalstate information and an estimated second signal state information suchthat the estimated linear process is an estimate of a linear process.The linear process may be based on the signal state information and thesecond signal state information. The estimated second signal stateinformation may be an estimate of the second signal state information.

In Example 9, the subject matter of Example 8 can optionally includethat the first vector may be determined such that the first vector is afirst eigenvector based on the estimated linear process. The secondvector may be a second eigenvector based on the estimated linearprocess. An eigenvalue of the first eigenvector based on the estimatedlinear process may be smaller than an eigenvalue of the secondeigenvector based on the estimated linear process.

In Example 10, the subject matter of Example 8 can optionally includethat the first vector may be determined such that the first vector is afirst eigenvector based on the estimated linear process. The secondvector may be the sum of second eigenvectors based on the estimatedlinear process. An eigenvalue of the first eigenvector based on theestimated linear process may be smaller than eigenvalues of the secondeigenvectors based on the estimated linear process.

In Example 11, the subject matter of Example 11 can optionally includethat the first vector may be determined such that the first vector isthe sum of first eigenvectors based on the estimated linear process. Thesecond vector may be a second eigenvector based on the estimated linearprocess. Eigenvalues of the first eigenvectors based on the estimatedlinear process may be smaller than an eigenvalue of the secondeigenvector based on the estimated linear process.

In Example 12, the subject matter of Example 8 can optionally includethat the first vector may be determined such that the first vector isthe sum of first eigenvectors based on the estimated linear process. Thesecond vector may be the sum of second eigenvectors based on theestimated linear process. Eigenvalues of the first eigenvectors based onthe estimated linear process may be smaller than a smallest eigenvalueof eigenvalues of the second eigenvectors based on the estimated linearprocess.

In Example 13, the subject matter of any one of Examples 1 to 12 canoptionally include that the circuit may be configured to determine asecond projection information. The second projection information may bedetermined based on an estimated third signal state information suchthat an energy of a shaped projected fourth signal is smaller than anenergy of a shaped fourth signal. A third signal state information maybe based on a fifth signal that may be transmitted from a fourthcommunication device and a received fifth signal that may be received bythe receiver of the second communication device. The estimated thirdsignal state information may be an estimate of the third signal stateinformation. The projected fourth signal may be projected based on thesecond projection information and a fourth signal. The shaped projectedfourth signal may be shaped based on the projected fourth signal thatmay be transmitted from the fourth communication device, received by thereceiver of the second communication device and filtered by the filter.The shaped fourth signal may be shaped based on the fourth signal thatmay be transmitted from the fourth communication device, received by thereceiver of the second communication device and filtered by the filter.

In Example 14, the subject matter of Example 13 can optionally includethat the projected fourth signal may be based on a fifth vector of inputsignals. The fifth vector may be based on a fifth plurality of inputsignals. The fourth signal may be based on a sixth vector of inputsignals. The sixth vector may be based on a sixth plurality of inputsignals.

In Example 15, the subject matter of Example 14 can optionally includethat the shaped projected fourth signal may be based on a seventh vectorof output signals. The seventh vector may be based on a seventhplurality of output signals that may be received by the receiver of thesecond communication device based on the projected fourth signal. Theshaped fourth signal may be based on an eighth vector of output signals.The eighth vector may be based on an eighth plurality of output signalsthat may be received by the receiver of the second communication devicebased on the fourth signal.

In Example 16, the subject matter of Example 15 can optionally includethat the signals of the fifth vector may be transmitted from the fourthcommunication device based on antennas of a second plurality of antennasof the fourth communication device, respectively. The signals of thesixth vector may be transmitted from the fourth communication devicebased on the antennas of the second plurality of antennas, respectively.

In Example 17, the subject matter of any one of Examples 15 to 16 canoptionally include that the second projection information may bedetermined such that a third absolute value of a third scalar product ofthe fifth vector and the seventh vector is smaller than a fourthabsolute value of a fourth scalar product of the sixth vector and theeighth vector.

In Example 18, the subject matter of any one of Examples 13 to 17 canoptionally include that the second projection information may bedetermined based on an estimated second linear process. The circuit maybe configured to determine the estimated second linear process based onthe estimated second signal state information and an estimated thirdsignal state information such that the estimated second linear processis an estimate of a second linear process. The second linear process maybe based on the third signal state information and the second signalstate information. The estimated third signal state information may bean estimate of the third signal state information.

In Example 19, the subject matter of Example 18 can optionally includethat the second projection information may be determined such that thefifth vector is a third eigenvector based on the estimated second linearprocess. The sixth vector may be a fourth eigenvector based on theestimated second linear process. An eigenvalue of the third eigenvectorbased on the estimated second linear process may be smaller than aneigenvalue of the fourth eigenvector based on the estimated secondlinear process.

In Example 20, the subject matter of Example 18 can optionally includethat the second projection information may be determined such that thefifth vector is a third eigenvector based on the estimated second linearprocess. The sixth vector may be the sum of fourth eigenvectors based onthe estimated second linear process. An eigenvalue of the thirdeigenvector based on the estimated second linear process may be smallerthan eigenvalues of the fourth eigenvectors based on the estimatedsecond linear process.

In Example 21, the subject matter of Example 18 can optionally includethat the second projection information may be determined such that thefifth vector is the sum of third eigenvectors based on the estimatedsecond linear process. The sixth vector may be a fourth eigenvectorbased on the estimated second linear process. Eigenvalues of the thirdeigenvectors based on the estimated second linear process may be smallerthan an eigenvalue of the fourth eigenvector based on the estimatedsecond linear process.

In Example 22, the subject matter of Example 18 can optionally includethat the second projection information may be determined such that thefifth vector is the sum of third eigenvectors based on the estimatedsecond linear process. The sixth vector may be the sum of fourtheigenvectors based on the estimated second linear process. Eigenvaluesof the third eigenvectors based on the estimated second linear processmay be smaller than a smallest eigenvalue of eigenvalues of the fourtheigenvectors based on the estimated second linear process.

In Example 23, the subject matter of any one of Examples 1 to 22 canoptionally include that the circuit may be configured to determine theestimated signal state information based on an interpolation of areceived signal that may be received from the first communication devicebased on the first signal, and a received signal that may be receivedfrom a fifth communication device based on a sixth signal that may betransmitted by the transmitter.

In Example 24, the subject matter of Example 23 can optionally includethat the estimated second signal state information may be determinedbased on an interpolation of a received signal that may be received fromthe first communication device based on a seventh signal that may betransmitted from the third communication device, and a received signalthat may be received from the fifth communication device based on aneighth signal that may be transmitted from the third communicationdevice.

In Example 25, the subject matter of Example 24 can optionally includethat the projected signal may be projected based on a first projectioninformation. The circuit may be configured to determine the firstprojection information based on the estimated linear process, aninterpolated first signal and an interpolated second signal such that afifth absolute value of a fifth scalar product of a projectedinterpolated first signal and an interpolated shaped projectedinterpolated first signal is smaller than a sixth absolute value of asixth scalar product of the interpolated first signal and aninterpolated shaped interpolated first signal. The interpolated firstsignal may be interpolated based on the first signal and the sixthsignal. The interpolated second signal may be interpolated based on theseventh signal and the eighth signal. A shaped interpolated first signalmay be shaped based on the interpolated first signal in correspondenceto the estimated linear process. The projected interpolated first signalmay be projected based on the interpolated first signal and the firstprojection information. A shaped projected interpolated first signal maybe shaped based on the projected interpolated first signal incorrespondence to the estimated linear process. A shaped interpolatedsecond signal may be shaped based on the interpolated second signal incorrespondence to the estimated linear process. A projected interpolatedsecond signal may be projected based on the interpolated second signaland the first projection information. A shaped projected interpolatedsecond signal may be shaped based on the projected interpolated secondsignal in correspondence to the estimated linear process. Theinterpolated shaped interpolated first signal may be interpolated basedon the shaped interpolated first signal and the shaped interpolatedsecond signal. The interpolated shaped projected interpolated firstsignal may be interpolated based on the shaped projected interpolatedfirst signal and the shaped projected interpolated second signal.

In Example 26, the subject matter of any one of Examples 24 to 25 canoptionally include that the estimated third signal state information maybe based on an interpolation of a received signal that may be receivedfrom the first communication device based on a ninth signal that may betransmitted from the fourth communication device, and a received signalthat may be received from the fifth communication device based on atenth signal that may be transmitted from the fourth communicationdevice.

In Example 27, the subject matter of Example 26 can optionally includethat the second projection information may be determined based on theestimated second linear process, the interpolated second signal and aninterpolated third signal such that a seventh absolute value of aseventh scalar product of a projected interpolated third signal and aninterpolated shaped projected interpolated third signal is smaller thanan eighth absolute value of an eighth scalar product of the interpolatedthird signal and an interpolated shaped interpolated third signal. Theinterpolated third signal may be interpolated based on the ninth signaland the tenth signal. A shaped interpolated third signal may be shapedbased on the interpolated third signal in correspondence to theestimated second linear process. The projected interpolated third signalmay be projected based on the interpolated third signal and the secondprojection information. A shaped projected interpolated third signal maybe shaped based on the projected interpolated third signal incorrespondence to the estimated second linear process. A shapedinterpolated fourth signal may be shaped based on the interpolatedsecond signal in correspondence to the estimated second linear process.A projected interpolated fourth signal may be projected based on theinterpolated second signal and the second projection information. Ashaped projected interpolated fourth signal may be shaped based on theprojected interpolated fourth signal in correspondence to the estimatedsecond linear process. The interpolated shaped interpolated third signalmay be interpolated based on the shaped interpolated third signal andthe shaped interpolated fourth signal. The interpolated shaped projectedinterpolated third signal may be interpolated based on the shapedprojected interpolated third signal and the shaped projectedinterpolated fourth signal.

In Example 28, the subject matter of any one of Examples 25 to 27 canoptionally include that the circuit may be configured to determine afirst weight factor based on a first distance of the first communicationdevice from the second communication device and a second weight factorbased on a second distance of the fifth communication device from thesecond communication device. The first projection information may bedetermined based on the weight factors.

In Example 29, the subject matter of Example 28 can optionally includethat the second projection information may be determined based on theweight factors.

In Example 30, the subject matter of any one of Examples 1 to 22 canoptionally include that the circuit may be configured to determine afourth signal state information that may be based on a received signalthat may be received from the first communication device based on thefirst signal. The estimated signal state information may be the fourthsignal state information.

In Example 31, the subject matter of any one of Examples 8 to 30 canoptionally include that the circuit may be configured to determine afifth signal state information that may be based on a received signalthat may be received from the first communication device based on thethird signal. The estimated second signal state information may be thefifth signal state information.

In Example 32, the subject matter of any one of Examples 13 to 31 canoptionally include that the circuit may be configured to determine asixth signal state information that may be based on a received signalthat may be received from the first communication device based on thefifth signal. The estimated third signal state information may be thesixth signal state information.

In Example 33, the subject matter of any one of Examples 1 to 32 canoptionally include that the receiver may be configured to receivesignals based on a frequency of signals that may be transmitted from thesecond communication device based on a shared frequency. The projectedsignal may be based on the shared frequency.

In Example 34, the subject matter of Example 33 can optionally includethat the communication device and the second communication device may beregistered in a control device to transmit based on the shared frequencyin a shared area.

In Example 35, the subject matter of Example 34 can optionally includethat the first communication device may be in the shared area.

In Example 36, the subject matter of any one of Examples 1 to 35 canoptionally include that the circuit may be configured to select thefirst communication device from a plurality of communication devicessuch that a distance of the first communication device from the secondcommunication device may be a smallest distance from the distances ofthe communication devices of the plurality of communication devices fromthe second communication device.

In Example 37, the subject matter of any one of Examples 1 to 36 canoptionally include that the signal state information may be based on afirst linear transfer function that maps the first signal to thereceived signal.

In Example 38, the subject matter of any one of Examples 7 to 37 canoptionally include that the second signal state information may be basedon a second linear transfer function that maps the third signal to thereceived third signal.

In Example 39, the subject matter of any one of Examples 13 to 38 canoptionally include that the third signal state information may be basedon a third linear transfer function that maps the fifth signal to thereceived fifth signal.

In Example 40, the subject matter of any one of Examples 1 to 39 canoptionally include that the first signal, the third signal and the fifthsignal may be based on an Evolved Universal Terrestrial Radio Accesscommunication technology.

In Example 41, the subject matter of Example 40 can optionally includethat the first signal, the third signal and/or the fifth signal includea pilot signal.

In Example 42, the subject matter of any one of Examples 1 to 41 canoptionally include that the filter may be configured to filter based onmaximal ratio combining.

In Example 43, the subject matter of any one of Examples 1 to 42 canoptionally include that the received signal may be received based on thefirst signal.

Example 44 is a communication device. The communication device mayinclude a receiver configured to receive signals from a firstcommunication device. Further, the communication device may include acircuit configured to determine a formed signal based on a locationinformation of a second communication device such that a received secondenergy based on the formed signal that may be received from the secondcommunication device is smaller than a received first energy based onthe formed signal that may be received from the first communicationdevice.

In Example 45, the subject matter of Example 44 can optionally includethat a received signal that may be received from the first communicationdevice may include the location information.

In Example 46, the subject matter of any one of Examples 44 to 45 canoptionally include that the formed signal may be determined based on atleast one of a group of communication technologies consisting of SingleInput Single Output, Single Input Multiple Output, Multiple Input SingleOutput, Multiple Input Multiple Output, beamforming, time multiplexingand frequency multiplexing.

In Example 47, the subject matter of any one of Examples 44 to 46 canoptionally include that the circuit may be configured to determine ifthe first communication device is able to transmit second formed signalssuch that second received energies based on the second formed signalsthat may be received from the second communication device may be smallerthan first received energies based on the second formed signals that maybe received from the first communication device, respectively. Thecircuit may be configured to generate a grant message to allow the firstcommunication device to transmit the second formed signals.

In Example 48, the subject matter of any one of Examples 44 to 47 canoptionally include that the communication device and the secondcommunication device may be registered in a control device to transmitbased on a shared frequency in a shared area. The formed signal may bebased on the shared frequency.

In Example 49, the subject matter of any one of Examples 44 to 48 canoptionally include that the receiver may be configured to receive asignal from the second communication device that may include a secondfrequency information. The circuit may be configured to determine athird formed signal that may be transmitted based on the secondfrequency.

In Example 50, the subject matter of any one of Examples 44 to 49 canoptionally include that the communication device may further include atransmitter configured to transmit signals in a plurality of sectors ofan angular transmission distribution. The second communication devicemay be in a first sector of the plurality of sectors. The formed signalmay be formed such that a transmitted power of the formed signal thatmay be transmitted in the first sector is smaller than each of thetransmitted powers of the formed signal that may be transmitted insectors of the plurality of sectors that may be different from the firstsector.

In Example 51, the subject matter of Example 50 can optionally includethat the formed signal may be determined such that the formed signal isnot transmitted in the first sector.

In Example 52, the subject matter of Example 51 can optionally includethat the circuit may be configured to determine signals based on a thirdfrequency that may be different from the shared frequency and/or thesecond frequency. The transmitter may be configured to transmit thesignals to communication devices that may be located in the firstsector.

In Example 53, the subject matter of any one of Examples 44 to 49 canoptionally include that the communication device may further include atransmitter configured to transmit a first signal and the formed signal.The circuit may be configured to determine an estimated signal stateinformation. The estimated signal state information may be an estimateof a signal state information based on a received signal that may bereceived by a receiver of a second communication device based on thefirst signal. The formed signal may be determined based on the estimatedsignal state information such that an energy of a shaped formed signalis smaller than an energy of a shaped signal. The shaped formed signalmay be the formed signal received by the receiver of the secondcommunication device and filtered by a filter of the secondcommunication device. The shaped signal may be the received signalfiltered by the filter of the second communication device.

Example 54 is a communication device. The communication device mayinclude a receiver configured to receive a first signal from a basestation and a second signal from a first communication device. Further,the communication device may include a determination circuit configuredto determine a first power level of the first signal and a second powerlevel of the second signal. Further, the communication device mayinclude a circuit configured to determine a power ratio of the firstpower level to the second power level. The first signal and the secondsignal may be based on a shared frequency. The circuit may be configuredto determine a third signal that may include an interference parameterinformation based on the power ratio.

In Example 55, the subject matter of Example 54 can optionally includethat the interference parameter information may indicate if the powerratio is smaller than a threshold.

In Example 56, the subject matter of any one of Examples 54 to 55 canoptionally include that the receiver may be configured to receive afourth signal from a second communication device. The fourth signal maybe based on the shared frequency. The determination circuit may beconfigured to determine a third power level of the fourth signal. Thecircuit may be configured to determine a second power ratio of the thirdpower level to the second power level. The interference parameterinformation indicates if the second power ratio is smaller than a secondthreshold.

In Example 57, the subject matter of Example 56 can optionally includethat the receiver may be configured to receive signals from a thirdcommunication device based on the shared frequency. The receiver may beconfigured to receive a signal that may include the threshold and/or thesecond threshold from the third communication device.

In Example 58, the subject matter of any one of Examples 54 to 57 canoptionally include that the first signal and the second signal may bereceived at a first time. The receiver may be configured to receive afifth signal from the base station at a second time after the first timeand a sixth signal from the first communication device at the secondtime. The determination circuit may be configured to determine a fourthpower level of the fifth signal and a fifth power level of the sixthsignal. The circuit may be configured to determine a third power ratioof the fourth power level to the fifth power level. The circuit may beconfigured to determine a prevention signal to prevent the base stationfrom transmitting signals based on the shared frequency if the thirdpower ratio is equal to or greater than the threshold.

In Example 59, the subject matter of Example 58 can optionally includethat the receiver may be configured to receive a seventh signal that maybe based on the shared frequency from the second communication device atthe second time. The determination circuit may be configured todetermine a sixth power level of the seventh signal. The circuit may beconfigured to determine a fourth power ratio of the sixth power level tothe fifth power level. The prevention signal may be determined toprevent the second communication device from transmitting signals basedon the shared frequency if the fourth power ratio is equal to or greaterthan the second threshold.

In Example 60, the subject matter of any one of Examples 54 to 59 canoptionally include that the signals that may be received from thereceiver may be radio frequency signals.

In Example 61, the subject matter of any one of Examples 54 to 60 canoptionally include that the first signal, the fourth signal, the fifthsignal, the sixth signal and the seventh signal may be based on anEvolved Universal Terrestrial Radio Access communication technology.

In Example 62, the subject matter of Example 61 can optionally includethat the first signal, the fourth signal, the fifth signal, the sixthsignal and the seventh signal include pilot signals, respectively.

Example 63 is a base station. The base station may include a transmitterconfigured to transmit signals based on a shared frequency. Further, thebase station may include a receiver configured to receive a connectionrequest signal based on the shared frequency from a first communicationdevice. Further, the base station may include a circuit configured todetermine a first signal based on the shared frequency that may includea request information of an interference parameter. The circuit may beconfigured to determine signals based on the interference parameter totransmit based on the shared frequency.

In Example 64, the subject matter of Example 63 can optionally includethat the receiver may be configured to receive signals from a thirdcommunication device based on the shared frequency.

In Example 65, the subject matter of any one of Examples 63 to 64 canoptionally include that the interference parameter may be based on afirst power level of a received first signal and a second power level ofa received second signal. The received first signal may be received froma second communication device based on the first signal. The receivedsecond signal may be received from the second communication device basedon a second signal that may be transmitted from a fourth communicationdevice based on the shared frequency.

In Example 66, the subject matter of Example 65 can optionally includethat the interference parameter may be a power ratio of the first powerlevel to the second power level.

In Example 67, the subject matter of Example 66 can optionally includethat the determined signals may be determined if the power ratio issmaller than a threshold.

In Example 68, the subject matter of any one of Examples 65 to 67 canoptionally include that the receiver may be configured to receive athird signal from the second communication device that may include theinterference parameter.

In Example 69, the subject matter of any one of Examples 65 to 68 canoptionally include that the circuit may be configured to determine afourth signal that may include a second request information of a secondinterference parameter. The second interference parameter may be asecond power ratio of a third power level of a received fifth signalthat may be received from the second communication device based on afifth signal that may be transmitted from the first communication devicebased on the shared frequency to the second power level.

In Example 70, the subject matter of any one of Examples 65 to 69 canoptionally include that the circuit may be configured to select thesecond communication device from a plurality of communication devicessuch that a distance of the second communication device to the thirdcommunication device is a smallest distance from the distances of thecommunication devices of the plurality of communication devices to thethird communication device.

In Example 71, the subject matter of any one of Examples 63 to 70 canoptionally include that the first signal may include a reference signal.

In Example 72, the subject matter of any one of Examples 63 to 71 canoptionally include that the first signal may be based on an EvolvedUniversal Terrestrial Radio Access communication technology. The firstsignal may include a pilot signal.

Example 73 is a communication device. The communication device mayinclude a receiver configured to receive signals from base stations.Further, the communication device may include a circuit configured toselect a first base station from the base stations. A first signal maybe transmitted from the first base station and a received first signalmay be received from a second communication device. A second signal maybe transmitted from a third communication device and a received secondsignal may be received from the second communication device. A parametermay be based on a first power level of the received first signal and asecond power level of the received second signal. The first base stationmay be selected based on the parameter.

In Example 74, the subject matter of Example 73 can optionally includethat the receiver may be configured to receive signals from a fourthcommunication device based on a shared frequency. The received signalsfrom the base stations may be based on the shared frequency.

In Example 75, the subject matter of any one of Examples 73 to 74 canoptionally include that the received first signal may be received basedon the first signal. The received second signal may be received based onthe second signal.

In Example 76, the subject matter of Example 75 can optionally includethat the parameter may be a power ratio of the first power level to thesecond power level. The first base station may be selected if the powerratio is smaller than a threshold.

In Example 77, the subject matter of any one of Examples 73 to 76 canoptionally include that the circuit may be configured to determine asignal selection receive level S_(rxlev) of each signal that may bereceived from the base stations, the each signal may be a third signal,by

S _(rxlev) =Q _(rxlevmeas)−(Q _(rxlevmin) +Q _(rxlevminoffset))−max(P_(EMAX) −P _(PowerClass),0)−Q _(offsettemp).

Q_(rxlevmeas) may be a measured signal receive level of the thirdsignal, Q_(rxlevmin) may be a minimum required receive level,Q_(rxlevminoffset) may be a first offset, P_(EMAX) may be a maximumuplink transmission power level, P_(PowerClass) may be a maximum radiofrequency output power, P_(compensation) may be a compensation powerlevel and Q_(offsettemp) may be a temporarily applied offset. Thecircuit may be configured to determine a signal selection quality valueS_(qual) signal of the third byS_(qual)=Q_(qualmeas)−(Q_(qualmin)+Q_(qualminoffset))−Q_(offsettemp).Q_(qualmeas) may be a measured signal quality value of the third signal,Q_(qualmin) may be a minimum required quality level of the signal,Q_(qualminoffset) may be an offset that may be an offset to the signaledQ_(qualmin) and Q_(offsettemp) may be a temporarily applied offset. Thefirst base station may be only selected if the signal selection receivelevel S_(rxlev) of the third signal is greater than zero and the signalselection quality value S_(qual) of the third signal is greater thanzero.

In Example 78, the subject matter of Example 77 can optionally includethat the circuit may be configured to select a second base station fromthe base stations based on a second power ratio of a third power levelof a received fourth signal, the received fourth signal being receivedfrom the second communication device based on a fourth signal that maybe transmitted from the second base station, to the second power levelif the signal selection receive level S_(rxlev) of the third signal isequal to or smaller than zero or the signal selection quality valueS_(qual) of the third signal is equal to or smaller than zero or thepower ratio is greater than the threshold. The signal selection receivelevel S_(rxlev) of the fourth signal may be greater than zero and thesignal selection quality value S_(qual) of the fourth signal may begreater than zero.

In Example 79, the subject matter of any one of Examples 77 to 78 canoptionally include that the circuit may be configured to prevent theselection of the first base station if the signal selection receivelevel S_(rxlev) of the third signal is greater than zero, the signalselection quality value S_(qual) of the third signal is greater thanzero and the power ratio is smaller than the threshold.

In Example 80, the subject matter of any one of Examples 77 to 79 canoptionally include that the shared frequency may be one of a pluralityof shared frequencies. The circuit may be configured to select a secondfrequency of the plurality of shared frequencies based on a second powerratio of a second power level of a fifth signal, the fifth signal beingtransmitted from the first base station based on the second frequencyand received from the second communication device, to the second powerlevel if the signal selection receive level S_(rxlev) of the thirdsignal is equal to or smaller than zero or the signal selection qualityvalue S_(qual) of the third signal is equal to or smaller than zero orthe power ratio is equal to or greater than the threshold.

In Example 81, the subject matter of Example 80 can optionally includethat the circuit may be configured to prevent the selection of thesecond frequency if the signal selection receive level S_(rxlev) of theeach signal that may be received from the first base station based onthe shared frequency is greater than zero, the signal selection qualityvalue S_(qual) of the each signal that is received from the first basestation based on the shared frequency is greater than zero and the powerratio is smaller than the threshold.

In Example 82, the subject matter of any one of Examples 73 to 81 canoptionally include that the shared frequency may be one of a pluralityof shared frequencies. The power ratio may be one of a plurality ofpower ratios that may be received from the first base station. The powerratios of the plurality of power ratios may be ratios of first powerlevels of signals, the signals being transmitted from the first basestation based on the shared frequencies and received from the secondcommunication device, to the second power level. The circuit may beconfigured to prohibit the selection of the first base station if thepower ratios may be equal to or greater than the threshold.

In Example 83, the subject matter of Example 82 can optionally includethat the selection of the first base station may be prohibited during apredefined time period.

Example 84 is a communication system. The communication system mayinclude a first communication device configured to determine anestimated signal state information and a base station configured totransmit a first signal and a projected signal and to determine aprojected signal based on an estimated signal state information suchthat an energy of a shaped projected signal is smaller than an energy ofa shaped signal. The estimated signal state information may be anestimate of a signal state information based on the first signal and areceived signal that may be received by a receiver of a secondcommunication device. The shaped projected signal may be the projectedsignal received by the receiver of the second communication device andfiltered by a filter of the second communication device. The shapedsignal may be the received signal filtered by the filter of the secondcommunication device.

In Example 85, the subject matter of Example 84 can optionally includethat the projected signal may be determined in accordance with aMultiple Input Multiple Output communication technology.

In Example 86, the subject matter of any one of Examples 84 to 85 canoptionally include that the projected signal may be based on a firstvector of input signals. The first vector may be based on a firstplurality of input signals. The second signal may be based on a secondvector of input signals. The second vector may be based on a secondplurality of input signals.

In Example 87, the subject matter of Example 86 can optionally includethat the shaped projected signal may be based on a third vector ofoutput signals. The third vector may be based on a third plurality ofoutput signals that may be received by the receiver of the secondcommunication device based on the projected signal. The shaped signalmay be based on a fourth vector of output signals. The fourth vector maybe based on a fourth plurality of output signals that may be received bythe receiver of the second communication device based on the firstsignal.

In Example 88, the subject matter of Example 87 can optionally includethat the base station may be configured to transmit signals based on aplurality of antennas. The signals of the first vector may betransmitted based on the antennas of the plurality of antennas,respectively. The signals of the second vector may be transmitted basedon the antennas of the plurality of antennas, respectively.

In Example 89, the subject matter of any one of Examples 87 to 88 canoptionally include that the base station may be configured to determinethe first vector such that a first absolute value of a first scalarproduct of the first vector and the third vector is smaller than asecond absolute value of a second scalar product of the second vectorand the fourth vector.

Example 90 is a method for radio communication. The method may includetransmitting a first signal and a projected signal. Further, the methodmay include determining the projected signal based on an estimatedsignal state information such that an energy of a shaped projectedsignal is smaller than an energy of a shaped signal. The estimatedsignal state information may be an estimate of a signal stateinformation based on the first signal and a received signal that may bereceived by a receiver of a second communication device. The shapedprojected signal may be the projected signal received by the receiver ofthe second communication device and filtered by a filter of the secondcommunication device. The shaped signal may be the received signalfiltered by the filter of the second communication device.

In Example 91, the subject matter of Example 90 can optionally includethat the projected signal may be determined in accordance with aMultiple Input Multiple Output communication technology.

In Example 92, the subject matter of any one of Examples 90 to 91 canoptionally include that the projected signal may be based on a firstvector of input signals. The first vector may be based on a firstplurality of input signals. The first signal may be based on a secondvector of input signals. The second vector may be based on a secondplurality of input signals.

In Example 93, the subject matter of Example 92 can optionally includethat the shaped projected signal may be based on a third vector ofoutput signals. The third vector may be based on a third plurality ofoutput signals that may be received by the receiver of the secondcommunication device based on the projected signal. The shaped signalmay be based on a fourth vector of output signals. The fourth vector maybe based on a fourth plurality of output signals that may be received bythe receiver of the second communication device based on the firstsignal.

In Example 94, the subject matter of Example 93 can optionally includethat the method may further include transmitting signals based on aplurality of antennas. The signals of the first vector may betransmitted based on the antennas of the plurality of antennas,respectively. The signals of the second vector may be transmitted basedon the antennas of the plurality of antennas, respectively.

In Example 95, the subject matter of any one of Examples 93 to 94 canoptionally include that the method may further include determining thefirst vector such that a first absolute value of a first scalar productof the first vector and the third vector is smaller than a secondabsolute value of a second scalar product of the second vector and thefourth vector.

In Example 96, the subject matter of any one of Examples 90 to 95 canoptionally include that a second signal state information may be basedon a third signal that may be transmitted from a third communicationdevice and a received third signal that may be received by the receiverof the second communication device. The second signal state informationmay be an estimate of a channel state information. The filter may beconfigured to filter based on the channel state information.

In Example 97, the subject matter of Example 96 can optionally includethat the method may further include determining the projected signalbased on an estimated linear process. The method may further includedetermining the estimated linear process based on the estimated signalstate information and an estimated second signal state information suchthat the estimated linear process is an estimate of a linear process.The linear process may be based on the signal state information and thesecond signal state information. The estimated second signal stateinformation may be an estimate of the second signal state information.

In Example 98, the subject matter of Example 97 can optionally includethat the first vector may be determined such that the first vector is afirst eigenvector based on the estimated linear process. The secondvector may be a second eigenvector based on the estimated linearprocess. An eigenvalue of the first eigenvector based on the estimatedlinear process may be smaller than an eigenvalue of the secondeigenvector based on the estimated linear process.

In Example 99, the subject matter of Example 97 can optionally includethat the first vector may be determined such that the first vector is afirst eigenvector based on the estimated linear process. The secondvector may be the sum of second eigenvectors based on the estimatedlinear process. An eigenvalue of the first eigenvector based on theestimated linear process may be smaller than eigenvalues of the secondeigenvectors based on the estimated linear process.

In Example 100, the subject matter of Example 97 can optionally includethat the first vector may be determined such that the first vector isthe sum of first eigenvectors based on the estimated linear process. Thesecond vector may be a second eigenvector based on the estimated linearprocess. Eigenvalues of the first eigenvectors based on the estimatedlinear process may be smaller than an eigenvalue of the secondeigenvector based on the estimated linear process.

In Example 101, the subject matter of Example 97 can optionally includethat the first vector may be determined such that the first vector isthe sum of first eigenvectors based on the estimated linear process. Thesecond vector may be the sum of second eigenvectors based on theestimated linear process. Eigenvalues of the first eigenvectors based onthe estimated linear process may be smaller than a smallest eigenvalueof eigenvalues of the second eigenvectors based on the estimated linearprocess.

In Example 102, the subject matter of any one of Examples 90 to 101 canoptionally include that the method may further include determining asecond projection information. The second projection information may bedetermined based on an estimated third signal state information suchthat an energy of a shaped projected fourth signal is smaller than anenergy of a shaped fourth signal. A third signal state information maybe based on a fifth signal that may be transmitted from a fourthcommunication device and a received fifth signal that may be received bythe receiver of the second communication device. The estimated thirdsignal state information may be an estimate of the third signal stateinformation. The projected fourth signal may be projected based on thesecond projection information and a fourth signal. The shaped projectedfourth signal may be shaped based on the projected fourth signal thatmay be transmitted from the fourth communication device, received by thereceiver of the second communication device and filtered by the filterof the second communication device. The shaped fourth signal may beshaped based on the fourth signal that may be transmitted from thefourth communication device, received by the receiver of the secondcommunication device and filtered by the filter of the secondcommunication device.

In Example 103, the subject matter of Example 102 can optionally includethat the projected fourth signal may be based on a fifth vector of inputsignals. The fifth vector may be based on a fifth plurality of inputsignals. The fourth signal may be based on a sixth vector of inputsignals. The sixth vector may be based on a sixth plurality of inputsignals.

In Example 104, the subject matter of Example 103 can optionally includethat the shaped projected fourth signal may be based on a seventh vectorof output signals. The seventh vector may be based on a seventhplurality of output signals that may be received by the receiver of thesecond communication device based on the projected fourth signal. Theshaped fourth signal may be based on an eighth vector of output signals.The eighth vector may be based on an eighth plurality of output signalsthat may be received by the receiver of the second communication devicebased on the fourth signal.

In Example 105, the subject matter of Example 104 can optionally includethat the signals of the fifth vector may be transmitted from the fourthcommunication device based on antennas of a second plurality of antennasof the fourth communication device, respectively. The signals of thesixth vector may be transmitted from the fourth communication devicebased on the antennas of the second plurality of antennas, respectively.

In Example 106, the subject matter of any one of Examples 104 to 105 canoptionally include that the second projection information may bedetermined such that a third absolute value of a third scalar product ofthe fifth vector and the seventh vector is smaller than a fourthabsolute value of a fourth scalar product of the sixth vector and theeighth vector.

In Example 107, the subject matter of any one of Examples 102 to 106 canoptionally include that the method may further include determining anestimated second linear process based on the estimated second signalstate information and an estimated third signal state information suchthat the estimated second linear process is an estimate of a secondlinear process. The second linear process may be based on the thirdsignal state information and the second signal state information. Theestimated third signal state information may be an estimate of the thirdsignal state information. The second projection information may bedetermined based on an estimated second linear process.

In Example 108, the subject matter of Example 107 can optionally includethat the second projection information may be determined such that thefifth vector is a third eigenvector based on the estimated second linearprocess. The sixth vector may be a fourth eigenvector based on theestimated second linear process. An eigenvalue of the third eigenvectorbased on the estimated second linear process may be smaller than aneigenvalue of the fourth eigenvector based on the estimated secondlinear process.

In Example 109, the subject matter of Example 107 can optionally includethat the second projection information may be determined such that thefifth vector may be a third eigenvector based on the estimated secondlinear process. The sixth vector may be the sum of fourth eigenvectorsbased on the estimated second linear process. An eigenvalue of the thirdeigenvector based on the estimated second linear process may be smallerthan eigenvalues of the fourth eigenvectors based on the estimatedsecond linear process.

In Example 110, the subject matter of Example 107 can optionally includethat the second projection information may be determined such that thefifth vector is the sum of third eigenvectors based on the estimatedsecond linear process. The sixth vector may be a fourth eigenvectorbased on the estimated second linear process. Eigenvalues of the thirdeigenvectors based on the estimated second linear process may be smallerthan an eigenvalue of the fourth eigenvector based on the estimatedsecond linear process.

In Example 111, the subject matter of Example 107 can optionally includethat the second projection information may be determined such that thefifth vector may be the sum of third eigenvectors based on the estimatedsecond linear process. The sixth vector may be the sum of fourtheigenvectors based on the estimated second linear process. Eigenvaluesof the third eigenvectors based on the estimated second linear processmay be smaller than a smallest eigenvalue of eigenvalues of the fourtheigenvectors based on the estimated second linear process.

In Example 112, the subject matter of any one of Examples 90 to 111 canoptionally include that the method may further include determining theestimated signal state information based on an interpolation of areceived signal that may be received from the first communication devicebased on the first signal, and a received signal that may be receivedfrom a fifth communication device based on a sixth signal that may betransmitted by the transmitter.

In Example 113, the subject matter of Example 112 can optionally includethat the estimated second signal state information may be determinedbased on an interpolation of a received signal that may be received fromthe first communication device based on a seventh signal that may betransmitted from the third communication device, and a received signalthat may be received from the fifth communication device based on aneighth signal that may be transmitted from the third communicationdevice.

In Example 114, the subject matter of Example 113 can optionally includethat the method may further include determining the first projectioninformation based on the estimated linear process, an interpolated firstsignal and an interpolated second signal such that a fifth absolutevalue of a fifth scalar product of a projected interpolated first signaland an interpolated shaped projected interpolated first signal issmaller than a sixth absolute value of a sixth scalar product of theinterpolated first signal and an interpolated shaped interpolated firstsignal. The projected signal may be projected based on a firstprojection information. The interpolated first signal may beinterpolated based on the first signal and the sixth signal. Theinterpolated second signal may be interpolated based on the seventhsignal and the eighth signal. A shaped interpolated first signal may beshaped based on the interpolated first signal in correspondence to theestimated linear process. The projected interpolated first signal may beprojected based on the interpolated first signal and the firstprojection information. A shaped projected interpolated first signal maybe shaped based on the projected interpolated first signal incorrespondence to the estimated linear process. A shaped interpolatedsecond signal may be shaped based on the interpolated second signal incorrespondence to the estimated linear process. A projected interpolatedsecond signal may be projected based on the interpolated second signaland the first projection information. A shaped projected interpolatedsecond signal may be shaped based on the projected interpolated secondsignal in correspondence to the estimated linear process. Theinterpolated shaped interpolated first signal may be interpolated basedon the shaped interpolated first signal and the shaped interpolatedsecond signal. The interpolated shaped projected interpolated firstsignal may be interpolated based on the shaped projected interpolatedfirst signal and the shaped projected interpolated second signal.

In Example 115, the subject matter of any one of Examples 113 to 114 canoptionally include that the estimated third signal state information maybe based on an interpolation of a received signal that may be receivedfrom the first communication device based on a ninth signal that may betransmitted from the fourth communication device, and a received signalthat may be received from the fifth communication device based on atenth signal that may be transmitted from the fourth communicationdevice.

In Example 116, the subject matter of Example 115 can optionally includethat the second projection information may be determined based on theestimated second linear process, the interpolated second signal and aninterpolated third signal such that a seventh absolute value of aseventh scalar product of a projected interpolated third signal and aninterpolated shaped projected interpolated third signal is smaller thanan eighth absolute value of an eighth scalar product of the interpolatedthird signal and an interpolated shaped interpolated third signal. Theinterpolated third signal may be interpolated based on the ninth signaland the tenth signal. A shaped interpolated third signal may be shapedbased on the interpolated third signal in correspondence to theestimated second linear process. The projected interpolated third signalmay be projected based on the interpolated third signal and the secondprojection information. A shaped projected interpolated third signal maybe shaped based on the projected interpolated third signal incorrespondence to the estimated second linear process. A shapedinterpolated fourth signal may be shaped based on the interpolatedsecond signal in correspondence to the estimated second linear process.A projected interpolated fourth signal may be projected based on theinterpolated second signal and the second projection information. Ashaped projected interpolated fourth signal may be shaped based on theprojected interpolated fourth signal in correspondence to the estimatedsecond linear process. The interpolated shaped interpolated third signalmay be interpolated based on the shaped interpolated third signal andthe shaped interpolated fourth signal. The interpolated shaped projectedinterpolated third signal may be interpolated based on the shapedprojected interpolated third signal and the shaped projectedinterpolated fourth signal.

In Example 117, the subject matter of any one of Examples 114 to 116 canoptionally include that the method may further include determining afirst weight factor based on a first distance of the first communicationdevice from the second communication device and a second weight factorbased on a second distance of the fifth communication device from thesecond communication device. The first projection information may bedetermined based on the weight factors.

In Example 118, the subject matter of Example 117 can optionally includethat the second projection information may be determined based on theweight factors.

In Example 119, the subject matter of any one of Examples 90 to 111 canoptionally include that the method may further include determining afourth signal state information that may be based on a received signalthat may be received from the first communication device based on thefirst signal. The estimated signal state information may be the fourthsignal state information.

In Example 120, the subject matter of any one of Examples 97 to 119 canoptionally include that the method may further include determining afifth signal state information that may be based on a received signalthat may be received from the first communication device based on thethird signal. The estimated second signal state information may be thefifth signal state information.

In Example 121, the subject matter of any one of Examples 102 to 120 canoptionally include that the method may further include determining asixth signal state information that may be based on a received signalthat may be received from the first communication device based on thefifth signal. The estimated third signal state information may be thesixth signal state information.

In Example 122, the subject matter of any one of Examples 90 to 121 canoptionally include that the method may further include receiving signalsbased on a frequency of signals that may be transmitted from the secondcommunication device based on a shared frequency. The projected signalmay be based on the shared frequency.

In Example 123, the subject matter of any one of Examples 90 to 121 canoptionally include that the communication device and the secondcommunication device may be registered in a control device to transmitbased on the shared frequency in a shared area.

In Example 124, the subject matter of Example 123 can optionally includethat the first communication device may be in the shared area.

In Example 125, the subject matter of any one of Examples 90 to 124 canoptionally include that the method may further include selecting thefirst communication device from a plurality of communication devicessuch that a distance of the first communication device from the secondcommunication device may be a smallest distance from the distances ofthe communication devices of the plurality of communication devices fromthe second communication device.

In Example 126, the subject matter of any one of Examples 90 to 125 canoptionally include that the signal state information may be based on afirst linear transfer function that maps the first signal to thereceived signal.

In Example 127, the subject matter of any one of Examples 90 to 125 canoptionally include that the second signal state information may be basedon a second linear transfer function that maps the third signal to thereceived third signal.

In Example 128, the subject matter of any one of Examples 102 to 127 canoptionally include that the third signal state information may be basedon a third linear transfer function that maps the fifth signal to thereceived fifth signal.

In Example 129, the subject matter of any one of Examples 90 to 128 canoptionally include that the first signal, the third signal and the fifthsignal may be based on an Evolved Universal Terrestrial Radio Accesscommunication technology.

In Example 130, the subject matter of any one of Examples 90 to 128 canoptionally include that the first signal, the third signal and/or thefifth signal include a pilot signal.

In Example 131, the subject matter of any one of Examples 90 to 130 canoptionally include that the filter may be configured to filter based onmaximal ratio combining.

In Example 132, the subject matter of any one of Examples 90 to 131 canoptionally include that the received signal may be received based on thefirst signal.

Example 133 is a method for radio communication. The method may includereceiving signals from a first communication device. The method mayfurther include determining a formed signal based on a locationinformation of a second communication device such that a received secondenergy based on the formed signal that may be received from the secondcommunication device is smaller than a received first energy based onthe formed signal that may be received from the first communicationdevice.

In Example 134, the subject matter of Example 133 can optionally includethat a received signal that may be received from the first communicationdevice may include the location information.

In Example 135, the subject matter of any one of Examples 133 to 134 canoptionally include that the formed signal may be determined based on atleast one of a group of communication technologies consisting of SingleInput Single Output, Single Input Multiple Output, Multiple Input SingleOutput, Multiple Input Multiple Output, beamforming, time multiplexingand frequency multiplexing.

In Example 136, the subject matter of any one of Examples 133 to 135 canoptionally include that the method may further include determining ifthe first communication device may be able to transmit second formedsignals such that second received energies based on the second formedsignals that may be received from the second communication device aresmaller than first received energies based on the second formed signalsthat may be received from the first communication device, respectively.The method may further include generating a grant message to allow thefirst communication device to transmit the second formed signals.

In Example 137, the subject matter of any one of Examples 133 to 136 canoptionally include that the second communication device may beregistered in a control device to transmit based on a shared frequencyin a shared area. The formed signal may be based on the sharedfrequency.

In Example 138, the subject matter of any one of Examples 133 to 137 canoptionally include that the method may further include receiving asignal from the second communication device that may include a secondfrequency information. The method may further include determining athird formed signal that may be transmitted based on the secondfrequency.

In Example 139, the subject matter of any one of Examples 133 to 138 canoptionally include that the method may further include transmittingsignals in a plurality of sectors of an angular transmissiondistribution. The second communication device may be in a first sectorof the plurality of sectors. The formed signal may be formed such that atransmitted power of the formed signal that may be transmitted in thefirst sector is smaller than each of the transmitted powers of theformed signal that may be transmitted in sectors of the plurality ofsectors that may be different from the first sector.

In Example 140, the subject matter of Example 139 can optionally includethat the formed signal may be determined such that the formed signal isnot transmitted in the first sector.

In Example 141, the subject matter of Example 140 can optionally includethat the method may further include determining signals based on a thirdfrequency that may be different from the shared frequency and/or thesecond frequency. The method may further include transmitting thesignals to communication devices that may be located in the firstsector.

In Example 142, the subject matter of any one of Examples 133 to 1411can optionally include that the method may further include transmittinga first signal and the formed signal. The method may further includedetermining an estimated signal state information. The estimated signalstate information may be an estimate of a signal state information basedon a received signal that may be received by a receiver of a secondcommunication device based on the first signal. The formed signal may bedetermined based on the estimated signal state information such that anenergy of a shaped formed signal is smaller than an energy of a shapedsignal. The shaped formed signal may be the formed signal received bythe receiver of the second communication device and filtered by a filterof the second communication device. The shaped signal may be thereceived signal filtered by the filter of the second communicationdevice.

Example 143 is a method for radio communication. The method may includereceiving a first signal from a base station and a second signal from afirst communication device. The method may further include determining afirst power level of the first signal and a second power level of thesecond signal. The method may further include determining a power ratioof the first power level to the second power level. The method mayfurther include determining a third signal that may include aninterference parameter information based on the power ratio. The firstsignal and the second signal may be based on a shared frequency.

In Example 144, the subject matter of Example 143 can optionally includethat the interference parameter information indicates if the power ratiois smaller than a threshold.

In Example 145, the subject matter of any one of Examples 143 to 144 canoptionally include that the method may further include receiving afourth signal from a second communication device. The method may furtherinclude determining a third power level of the fourth signal. The methodmay further include determining a second power ratio of the third powerlevel to the second power level. The fourth signal may be based on theshared frequency. The interference parameter information may indicate ifthe second power ratio is smaller than a second threshold.

In Example 146, the subject matter of Example 145 can optionally includethat the method may further include receiving signals from a thirdcommunication device based on the shared frequency. The method mayfurther include receiving a signal that may include the threshold and/orthe second threshold from the third communication device.

In Example 147, the subject matter of any one of Examples 143 to 146 canoptionally include that the method may further include receiving a fifthsignal from the base station at a second time after a first time and asixth signal from the first communication device at the second time. Thefirst signal and the second signal may be received at the first time.The method may further include determining a fourth power level of thefifth signal and a fifth power level of the sixth signal. The method mayfurther include determining a third power ratio of the fourth powerlevel to the fifth power level. The method may further includedetermining a prevention signal to prevent the base station fromtransmitting signals based on the shared frequency if the third powerratio is equal to or greater than the threshold.

In Example 148, the subject matter of Example 147 can optionally includethat the method may further include receiving a seventh signal that maybe based on the shared frequency from the second communication device atthe second time. The method may further include determining a sixthpower level of the seventh signal. The method may further includedetermining a fourth power ratio of the sixth power level to the fifthpower level. The prevention signal may be determined to prevent thesecond communication device from transmitting signals based on theshared frequency if the fourth power ratio is equal to or greater thanthe second threshold.

In Example 149, the subject matter of any one of Examples 143 to 148 canoptionally include that the signals that may be received from thereceiver may be radio frequency signals.

In Example 150, the subject matter of any one of Examples 143 to 149 canoptionally include that the first signal, the fourth signal, the fifthsignal, the sixth signal and the seventh signal may be based on anEvolved Universal Terrestrial Radio Access communication technology.

In Example 151, the subject matter of Example 150 can optionally includethat the first signal, the fourth signal, the fifth signal, the sixthsignal and the seventh signal include pilot signals, respectively.

Example 152 is a method for radio communication. The method may includetransmitting signals based on a shared frequency. The method may furtherinclude receiving a connection request signal based on the sharedfrequency from a first communication device. The method may furtherinclude determining a first signal based on the shared frequency thatmay include a request information of an interference parameter. Themethod may further include determining signals based on the interferenceparameter to transmit based on the shared frequency.

In Example 153, the subject matter of Example 152 can optionally includethat the method may further include receiving signals from a thirdcommunication device based on the shared frequency.

In Example 154, the subject matter of any one of Examples 152 to 153 canoptionally include that the interference parameter may be based on afirst power level of a received first signal and a second power level ofa received second signal. The received first signal may be received froma second communication device based on the first signal. The receivedsecond signal may be received from the second communication device basedon a second signal that may be transmitted from a fourth communicationdevice based on the shared frequency.

In Example 155, the subject matter of Example 154 can optionally includethat the interference parameter may be a power ratio of the first powerlevel to the second power level.

In Example 156, the subject matter of Example 155 can optionally includethat the determined signals may be determined if the power ratio issmaller than a threshold.

In Example 157, the subject matter of any one of Examples 154 to 156 canoptionally include that the method may further include receiving a thirdsignal from the second communication device that may include theinterference parameter.

In Example 158, the subject matter of any one of Examples 154 to 157 canoptionally include that the method may further include determining afourth signal that may include a second request information of a secondinterference parameter. The second interference parameter may be asecond power ratio of a third power level of a received fifth signalthat may be received from the second communication device based on afifth signal that may be transmitted from the first communication devicebased on the shared frequency to the second power level.

In Example 159, the subject matter of any one of Examples 154 to 158 canoptionally include that the method may further include selecting thesecond communication device from a plurality of communication devicessuch that a distance of the second communication device to the thirdcommunication device is a smallest distance from the distances of thecommunication devices of the plurality of communication devices to thethird communication device.

In Example 160, the subject matter of any one of Examples 152 to 159 canoptionally include that the first signal may include a reference signal.

In Example 161, the subject matter of any one of Examples 152 to 160 canoptionally include that the first signal may be based on an EvolvedUniversal Terrestrial Radio Access communication technology. The firstsignal may include a pilot signal.

Example 162 is a method for radio communication. The method may includereceiving signals from base stations. The method may further includeselecting a first base station from the base stations. A first signalmay be transmitted from the first base station and a received firstsignal may be received from a second communication device. A secondsignal may be transmitted from a third communication device and areceived second signal may be received from the second communicationdevice. A parameter may be based on a first power level of the receivedfirst signal and a second power level of the received second signal. Thefirst base station may be selected based on the parameter.

In Example 163, the subject matter of Example 162 can optionally includethat the method may further include receiving signals from a fourthcommunication device based on a shared frequency. The received signalsfrom the base stations may be based on the shared frequency.

In Example 164, the subject matter of any one of Examples 162 to 163 canoptionally include that the received first signal may be received basedon the first signal. The received second signal may be received based onthe second signal.

In Example 165, the subject matter of Example 164 can optionally includethat the parameter may be a power ratio of the first power level to thesecond power level. The first base station may be selected if the powerratio is smaller than a threshold.

In Example 166, the subject matter of any one of Examples 162 to 165 canoptionally include that the method may further include determining asignal selection receive level S_(rxlev) of each signal that may bereceived from the base stations, the each signal being a third signal,by

S _(rxlev) =Q _(rxlevmeas)−(Q _(rxlevmin) +Q _(rxlevminoffset))−max(P_(EMAX) −P _(PowerClass),0)−Q _(offsettemp).

Q_(rxlevmeas) may be a measured signal receive level of the thirdsignal, Q_(rxlevmin) may be a minimum required receive level,Q_(rxlevminoffset) may be a first offset, P_(EMAX) may be a maximumuplink transmission power level, P_(PowerClass) may be a maximum radiofrequency output power, P_(compensation) may be a compensation powerlevel and Q_(offsettemp) may be a temporarily applied offset. The methodmay further include determining a signal selection quality valueS_(qual) of the third signal by

S _(qual) =Q _(qualmeas)−(Q _(qualmin) +Q _(qualminoffset))−Q_(offsettemp).

Q_(qualmeas) may be a measured signal quality value of the third signal,Q_(qualmin) may be a minimum required quality level of the signal,Q_(qualminoffset) may be an offset that may be an offset to the signaledQ_(qualmin) and Q_(offsettemp) may be a temporarily applied offset. Thefirst base station may be only selected if the signal selection receivelevel S_(rxlev) of the third signal is greater than zero and the signalselection quality value S_(qual) of the third signal is greater thanzero.

In Example 167, the subject matter of Example 166 can optionally includethat the method may further include selecting a second base station fromthe base stations based on a second power ratio of a third power levelof a received fourth signal, the received fourth signal being receivedfrom the second communication device based on a fourth signal that maybe transmitted from the second base station, to the second power levelif the signal selection receive level S_(rxlev) of the third signal isequal to or smaller than zero or the signal selection quality valueS_(qual) of the third signal is equal to or smaller than zero or thepower ratio is greater than the threshold. The signal selection receivelevel S_(rxlev) of the fourth signal may be greater than zero and thesignal selection quality value S_(qual) of the fourth signal may begreater than zero.

In Example 168, the subject matter of any one of Examples 166 to 167 canoptionally include that the method may further include preventing theselection of the first base station if the signal selection receivelevel S_(rxlev) of the third signal is greater than zero, the signalselection quality value S_(qual) of the third signal is greater thanzero and the power ratio is smaller than the threshold.

In Example 169, the subject matter of any one of Examples 166 to 168 canoptionally include that the method may further include selecting asecond frequency of a plurality of shared frequencies based on a secondpower ratio of a second power level of a fifth signal, the fifth signalbeing transmitted from the first base station based on the secondfrequency and received from the second communication device, to thesecond power level if the signal selection receive level S_(rxlev) ofthe third signal is equal to or smaller than zero or the signalselection quality value S_(qual) of the third signal is equal to orsmaller than zero or the power ratio is equal to or greater than thethreshold. The shared frequency may be one of a plurality of sharedfrequencies.

In Example 170, the subject matter of Example 169 can optionally includethat the method may further include preventing the selection of thesecond frequency if the signal selection receive level S_(rxlev) of theeach signal that may be received from the first base station based onthe shared frequency is greater than zero, the signal selection qualityvalue S_(qual) of the each signal that may be received from the firstbase station based on the shared frequency is greater than zero and thepower ratio is smaller than the threshold.

In Example 171, the subject matter of any one of Examples 162 to 170 canoptionally include that the method may further include prohibiting theselection of the first base station if the power ratios may be equal toor greater than the threshold. The power ratios of the plurality ofpower ratios may be ratios of first power levels of signals, the signalsbeing transmitted from the first base station based on the sharedfrequencies and received from the second communication device, to thesecond power level. The power ratio may be one of a plurality of powerratios that may be received from the first base station. The sharedfrequency may be one of a plurality of shared frequencies.

In Example 172, the subject matter of Example 171 can optionally includethat the selection of the first base station may be prohibited during apredefined time period.

Example 173 is a method for radio communication. The method may includedetermining an estimated signal state information. The method mayfurther include transmitting a first signal and a projected signal. Themethod may further include determining the projected signal based on anestimated signal state information such that an energy of a shapedprojected signal is smaller than an energy of a shaped signal. Theestimated signal state information may be an estimate of a signal stateinformation based on the first signal and a received signal that may bereceived by a receiver of a second communication device. The shapedprojected signal may be the projected signal received by the secondcommunication device and filtered by a filter of the secondcommunication device. The shaped signal may be the received signalfiltered by the filter of the second communication device.

In Example 174, the subject matter of Example 173 can optionally includethat the projected signal may be determined in accordance with aMultiple Input Multiple Output communication technology.

In Example 175, the subject matter of any one of Examples 173 to 174 canoptionally include that the projected signal may be based on a firstvector of input signals. The first vector may be based on a firstplurality of input signals. The second signal may be based on a secondvector of input signals. The second vector may be based on a secondplurality of input signals.

In Example 176, the subject matter of Example 175 can optionally includethat the shaped projected signal may be based on a third vector ofoutput signals. The third vector may be based on a third plurality ofoutput signals that may be received from the second communication devicebased on the projected signal. The shaped signal may be based on afourth vector of output signals. The fourth vector may be based on afourth plurality of output signals that may be received from the secondcommunication device based on the first signal.

In Example 177, the subject matter of Example 176 can optionally includethat the method may further include transmitting signals based on aplurality of antennas. The signals of the first vector may betransmitted based on the antennas of the plurality of antennas,respectively. The signals of the second vector may be transmitted basedon the antennas of the plurality of antennas, respectively.

In Example 178, the subject matter of any one of Examples 176 to 177 canoptionally include that the method may further include determining thefirst vector such that a first absolute value of a first scalar productof the first vector and the third vector is smaller than a secondabsolute value of a second scalar product of the second vector and thefourth vector.

Example 179 is a communication device. The communication device mayinclude a receiver configured to receive a received signal transmittedby another communication device. Further, the communication device mayinclude a filter configured to filter the received signal to therebygenerate a shaped signal. Further, the communication device may includea circuit configured to determine a filter characteristic vectorprovided to filter the received signal. Further, the communicationdevice may include a transmitter configured to transmit the informationrepresentative of the determined filter characteristic vector to theother communication device.

In Example 180, the subject matter of Example 179 can optionally includethat the receiver may be a multiple input multiple output receiver.

In Example 181, the subject matter of any one of Examples 179 to 180 canoptionally include that the filter may be configured to filter thereceived signal in accordance with a maximal ratio combining.

Example 182 is a method of operating a communication device. The methodmay include receiving a received signal transmitted by anothercommunication device. The method may further include filtering thereceived signal to thereby generate a shaped signal. The method mayfurther include determining a filter characteristic vector provided tofilter the received signal. The method may further include transmittingthe information representative of the determined filter characteristicvector to the other communication device.

In Example 183, the subject matter of Example 182 can optionally includethat the received signal may be received by a multiple input multipleoutput receiver.

In Example 184, the subject matter of any one of Examples 182 to 183 canoptionally include that the received signal may be filtered inaccordance with a maximal ratio combining.

In Example 185, the subject matter of any one of Examples 1 to 83 and179 to 181 can optionally include that the circuit is a basebandcircuit.

While the disclosure has been particularly shown and described withreference to specific aspects, it should be understood by those skilledin the art that various changes in form and detail may be made thereinwithout departing from the spirit and scope of the disclosure as definedby the appended claims. The scope of the disclosure is thus indicated bythe appended claims and all changes which come within the meaning andrange of equivalency of the claims are therefore intended to beembraced.

What is claimed is:
 1. A communication device, comprising: a transmitterconfigured to transmit a first signal, a third signal, and a projectedsignal; and a circuit configured to determine the projected signal basedon an estimated signal state information such that an energy of a shapedprojected signal is smaller than an energy of a shaped signal, wherein asignal state information is based on the first signal and a secondreceived signal that is received by a receiver of a second communicationdevice, wherein the estimated signal state information is determinedbased on an interpolation of a first received signal that is received bya first communication device and a third received signal that isreceived by a third communication device, wherein the first receivedsignal is received based on the first signal, wherein the third receivedsignal is received based on the third signal, wherein the estimatedsignal state information is an estimate of the signal state information,wherein the shaped projected signal is the projected signal received bythe receiver of the second communication device and filtered by a filterof the second communication device, wherein the shaped signal is thesecond received signal filtered by the filter of the secondcommunication device.
 2. The communication device of claim 1, whereinthe projected signal is determined in accordance with a Multiple InputMultiple Output communication technology.
 3. The communication device ofclaim 2, wherein the projected signal is based on a first vector ofinput signals, wherein the first vector is based on a first plurality ofinput signals, wherein the first signal is based on a second vector ofinput signals, and wherein the second vector is based on a secondplurality of input signals.
 4. The communication device of claim 3,wherein the shaped projected signal is based on a third vector of outputsignals, wherein the third vector is based on a third plurality ofoutput signals that are received by the receiver of the secondcommunication device based on the projected signal, wherein the shapedsignal is based on a fourth vector of output signals, and wherein thefourth vector is based on a fourth plurality of output signals that arereceived by the receiver of the second communication device based on thefirst signal.
 5. The communication device of claim 4, wherein thetransmitter is configured to transmit signals based on a plurality ofantennas, wherein the signals of the first vector are transmitted basedon the antennas of the plurality of antennas, respectively, and whereinthe signals of the second vector are transmitted based on the antennasof the plurality of antennas, respectively.
 6. The communication deviceof claim 1, wherein a second signal state information is based on athird signal that is transmitted from a fourth communication device anda received third signal that is received by the receiver of the secondcommunication device, wherein the second signal state information is anestimate of a channel state information, wherein the filter isconfigured to filter based on the channel state information, wherein thecircuit is configured to determine the projected signal based on anestimated linear process, wherein the circuit is configured to determinethe estimated linear process based on the estimated signal stateinformation and an estimated second signal state information such thatthe estimated linear process is an estimate of a linear process, whereinthe linear process is based on the signal state information and thesecond signal state information, and wherein the estimated second signalstate information is an estimate of the second signal state information.7. The communication device of claim 6, wherein the first vector isdetermined such that the first vector is the sum of first eigenvectorsbased on the estimated linear process, wherein the second vector is thesum of second eigenvectors based on the estimated linear process, andwherein eigenvalues of the first eigenvectors based on the estimatedlinear process are smaller than a smallest eigenvalue of eigenvalues ofthe second eigenvectors based on the estimated linear process.
 8. Thecommunication device of claim 7, wherein the receiver is configured toreceive signals based on a frequency of signals that are transmittedfrom the second communication device based on a shared frequency, andwherein the projected signal is based on the shared frequency.
 9. Thecommunication device of claim 8, wherein the circuit is configured toselect the first communication device from a plurality of communicationdevices such that a distance of the first communication device from thesecond communication device is a smallest distance from the distances ofthe communication devices of the plurality of communication devices fromthe second communication device.
 10. The communication device of claim9, wherein the signal state information is based on a first lineartransfer function that maps the first signal to the second receivedsignal.
 11. The communication device of claim 10, wherein the filter isconfigured to filter based on maximal ratio combining.
 12. Acommunication device, comprising: a receiver configured to receivesignals from a first communication device; and a circuit configured todetermine a formed signal based on a location information of a secondcommunication device such that a received second energy based on theformed signal that is received from the second communication device issmaller than a received first energy based on the formed signal that isreceived from the first communication device.
 13. The communicationdevice of claim 12, wherein a received signal that is received from thefirst communication device comprises the location information.
 14. Amethod for radio communications, comprising: transmitting a firstsignal, a third signal, and a projected signal; and determining theprojected signal based on an estimated signal state information suchthat an energy of a shaped projected signal is smaller than an energy ofa shaped signal, wherein a signal state information is based on thefirst signal and a second received signal that is received by a receiverof a second communication device, wherein the estimated signal stateinformation is determined based on an interpolation of a first receivedsignal that is received by a first communication device and a thirdreceived signal that is received by a third communication device,wherein the first received signal is received based on the first signal,wherein the third received signal is received based on the third signal,wherein the estimated signal state information is an estimate of thesignal state information, wherein the shaped projected signal is theprojected signal received by the receiver of the second communicationdevice and filtered by a filter of the second communication device, andwherein the shaped signal is the second received signal filtered by thefilter of the second communication device.